diff --git a/.github/workflows/test_urls.yml b/.github/workflows/test_urls.yml
index 2c5616a..f065462 100644
--- a/.github/workflows/test_urls.yml
+++ b/.github/workflows/test_urls.yml
@@ -22,12 +22,12 @@ jobs:
     ping_urls:
       runs-on: ubuntu-latest
       steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
       - name: Set up Python
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v5
         with:
-          python-version: 3.9
+          python-version: 3.12
 
       - name: Install testing dependencies
         run: |
diff --git a/src/openmc_data/__init__.py b/src/openmc_data/__init__.py
index 157f1c7..07081b6 100644
--- a/src/openmc_data/__init__.py
+++ b/src/openmc_data/__init__.py
@@ -17,9 +17,11 @@
 __all__ = ["__version__"]
 
 from .utils import (
+    ProgressTracker,
     calculate_download_size,
     download,
     extract,
+    format_duration,
     get_file_types,
     process_neutron,
     process_thermal,
diff --git a/src/openmc_data/convert/convert_endf.py b/src/openmc_data/convert/convert_endf.py
index 17817a7..685c109 100755
--- a/src/openmc_data/convert/convert_endf.py
+++ b/src/openmc_data/convert/convert_endf.py
@@ -11,7 +11,7 @@
 from pathlib import Path
 
 import openmc.data
-from openmc_data import download, extract, all_release_details, get_file_types, calculate_download_size
+from openmc_data import download, extract, all_release_details, get_file_types, calculate_download_size, ProgressTracker
 
 # Make sure Python version is sufficient
 assert sys.version_info >= (3, 6), "Python 3.6+ is required"
@@ -155,8 +155,10 @@ def main():
                 (openmc.data.IncidentNeutron, ace_files_dir.rglob(details["ace_files"])),
                 (openmc.data.ThermalScattering, ace_files_dir.rglob(details["sab_files"])),
             ]:
-                for path in sorted(files):
-                    print(f"Converting: {path.name}")
+                files = sorted(files)
+                tracker = ProgressTracker(len(files))
+                for path in files:
+                    tracker.starting(path.name)
                     data = cls.from_ace(path)
                     # Export HDF5 file
                     h5_file = args.destination.joinpath(particle, data.name + ".h5")
@@ -166,11 +168,13 @@ def main():
                     library.register_file(h5_file)
 
         elif particle == "photon":
-            for photo_path, atom_path in zip(
+            photon_pairs = list(zip(
                 sorted(endf_files_dir.glob(details["photo_files"])), sorted(endf_files_dir.glob(details["atom_files"]))
-            ):
+            ))
+            tracker = ProgressTracker(len(photon_pairs))
+            for photo_path, atom_path in photon_pairs:
                 # Generate instance of IncidentPhoton
-                print("Converting:", photo_path.name, atom_path.name)
+                tracker.starting(f"{photo_path.name} {atom_path.name}")
                 data = openmc.data.IncidentPhoton.from_endf(photo_path, atom_path)
 
                 # Export HDF5 file
diff --git a/src/openmc_data/convert/convert_fendl.py b/src/openmc_data/convert/convert_fendl.py
index 6043877..682cd83 100755
--- a/src/openmc_data/convert/convert_fendl.py
+++ b/src/openmc_data/convert/convert_fendl.py
@@ -14,7 +14,7 @@
 from urllib.parse import urljoin
 
 import openmc.data
-from openmc_data import download, all_release_details, calculate_download_size, get_file_types
+from openmc_data import download, all_release_details, calculate_download_size, get_file_types, ProgressTracker
 
 
 class CustomFormatter(
@@ -228,7 +228,9 @@ def main():
                 if not f.name.endswith("_") and not f.name.endswith(".xsd")
             ]
 
-            for filename in sorted(neutron_files):
+            neutron_files = sorted(neutron_files)
+            tracker = ProgressTracker(len(neutron_files))
+            for filename in neutron_files:
                 # Handling for special cases
                 if filename.name in special_cases:
                     ret = special_cases[filename.name](filename)
@@ -237,7 +239,7 @@ def main():
                     if ret["skip_file"]:
                         continue
 
-                print(f"Converting: {filename}")
+                tracker.starting(filename)
                 data = openmc.data.IncidentNeutron.from_ace(filename)
 
                 # Export HDF5 file
@@ -258,7 +260,9 @@ def main():
                 release_details[args.release]["photon"][file_types[particle]]["endf_files"]
             )
 
-            for photo_path in sorted(photon_files):
+            photon_files = sorted(photon_files)
+            photon_tracker = ProgressTracker(len(photon_files))
+            for photo_path in photon_files:
 
                 # Check if file requires special handling
                 if photo_path.name in special_cases:
@@ -268,7 +272,7 @@ def main():
                     if ret["skip_file"]:
                         continue
 
-                print(f"Converting: {photo_path}")
+                photon_tracker.starting(photo_path)
                 evaluations = openmc.data.endf.get_evaluations(photo_path)
                 for ev in evaluations:
                     # Export HDF5 file
diff --git a/src/openmc_data/convert/convert_jeff32.py b/src/openmc_data/convert/convert_jeff32.py
index dee634e..10c6386 100755
--- a/src/openmc_data/convert/convert_jeff32.py
+++ b/src/openmc_data/convert/convert_jeff32.py
@@ -14,7 +14,7 @@
 from urllib.parse import urljoin
 
 import openmc.data
-from openmc_data import download, calculate_download_size, all_release_details, get_file_types
+from openmc_data import download, calculate_download_size, all_release_details, get_file_types, ProgressTracker
 
 
 class CustomFormatter(
@@ -196,9 +196,11 @@ def main():
 
     library = openmc.data.DataLibrary()
 
-    for name, filenames in sorted(tables.items()):
+    neutron_tables = sorted(tables.items())
+    tracker = ProgressTracker(len(neutron_tables))
+    for name, filenames in neutron_tables:
         # Convert first temperature for the table
-        print("Converting: " + str(filenames[0]))
+        tracker.starting(filenames[0])
         data = openmc.data.IncidentNeutron.from_ace(filenames[0])
 
         # For each higher temperature, add cross sections to the existing table
@@ -228,9 +230,11 @@ def main():
     for name, filenames in sorted(tables.items()):
         filenames.sort(key=lambda x: int(x.name.split("-")[1].split(".")[0]))
 
-    for name, filenames in sorted(tables.items()):
+    sab_tables = sorted(tables.items())
+    sab_tracker = ProgressTracker(len(sab_tables))
+    for name, filenames in sab_tables:
         # Convert first temperature for the table
-        print(f"Converting: {filenames[0]}")
+        sab_tracker.starting(filenames[0])
 
         # Take numbers out of table name, e.g. lw10.32t -> lw.32t
         table = openmc.data.ace.get_table(filenames[0])
diff --git a/src/openmc_data/convert/convert_jeff33.py b/src/openmc_data/convert/convert_jeff33.py
index 74b05d8..05041a3 100755
--- a/src/openmc_data/convert/convert_jeff33.py
+++ b/src/openmc_data/convert/convert_jeff33.py
@@ -13,7 +13,7 @@
 
 import openmc.data
 
-from openmc_data import download, extract, calculate_download_size, all_release_details, get_file_types
+from openmc_data import download, extract, calculate_download_size, all_release_details, get_file_types, ProgressTracker
 
 
 # Make sure Python version is sufficient
@@ -153,8 +153,10 @@ def main():
 
     lib = openmc.data.DataLibrary()
 
-    for p in sorted(ace_files_dir.glob(details['neutron_files']), key=key):
-        print(f"Converting: {p}")
+    neutron_paths = sorted(ace_files_dir.glob(details['neutron_files']), key=key)
+    tracker = ProgressTracker(len(neutron_paths))
+    for p in neutron_paths:
+        tracker.starting(p)
         temp, z, a, m = key(p)
 
         data = openmc.data.IncidentNeutron.from_ace(p)
@@ -203,12 +205,13 @@ def thermal_temp(p):
 
     thermal_dir = ace_files_dir / details["thermal_files"]
 
+    thermal_tracker = ProgressTracker(len(thermal_mats))
     for mat in thermal_mats:
         for i, p in enumerate(
             sorted(thermal_dir.glob(f"{mat}*.ace"), key=thermal_temp)
         ):
             if i == 0:
-                print(f"Converting: {p}")
+                thermal_tracker.starting(p)
                 data = openmc.data.ThermalScattering.from_ace(p)
             else:
                 print(f"Adding temperature: {p}")
diff --git a/src/openmc_data/convert/convert_lib80x.py b/src/openmc_data/convert/convert_lib80x.py
index 36be10b..37a23e3 100755
--- a/src/openmc_data/convert/convert_lib80x.py
+++ b/src/openmc_data/convert/convert_lib80x.py
@@ -13,6 +13,8 @@
 
 import openmc.data
 
+from openmc_data import ProgressTracker
+
 
 # Make sure Python version is sufficient
 assert sys.version_info >= (3, 6), "Python 3.6+ is required"
@@ -76,10 +78,12 @@ def main():
 
     library = openmc.data.DataLibrary()
 
-    for name, paths in sorted(tables.items()):
+    sorted_tables = sorted(tables.items())
+    tracker = ProgressTracker(len(sorted_tables))
+    for name, paths in sorted_tables:
         # Convert first temperature for the table
         p = paths[0]
-        print(f'Converting: {p}')
+        tracker.starting(p)
         if p.name.endswith('t'):
             data = openmc.data.ThermalScattering.from_ace(p)
         else:
diff --git a/src/openmc_data/convert/convert_mcnp70.py b/src/openmc_data/convert/convert_mcnp70.py
index 1006693..bd84ce3 100755
--- a/src/openmc_data/convert/convert_mcnp70.py
+++ b/src/openmc_data/convert/convert_mcnp70.py
@@ -15,6 +15,8 @@
 
 import openmc.data
 
+from openmc_data import ProgressTracker
+
 
 # Make sure Python version is sufficient
 assert sys.version_info >= (3, 6), "Python 3.6+ is required"
@@ -68,9 +70,11 @@ def main():
             zaid, xs = table.name.split('.')
             tables[zaid].append(table)
 
-        for zaid, tables in sorted(tables.items()):
+        neutron_groups = sorted(tables.items())
+        tracker = ProgressTracker(len(neutron_groups))
+        for zaid, tables in neutron_groups:
             # Convert first temperature for the table
-            print(f'Converting: {tables[0].name}')
+            tracker.starting(tables[0].name)
             data = openmc.data.IncidentNeutron.from_ace(tables[0], 'mcnp')
 
             # For each higher temperature, add cross sections to the existing table
@@ -97,9 +101,11 @@ def main():
             name, xs = table.name.split('.')
             tables[name].append(table)
 
-        for zaid, tables in sorted(tables.items()):
+        sab_groups = sorted(tables.items())
+        tracker = ProgressTracker(len(sab_groups))
+        for zaid, tables in sab_groups:
             # Convert first temperature for the table
-            print(f'Converting: {tables[0].name}')
+            tracker.starting(tables[0].name)
             data = openmc.data.ThermalScattering.from_ace(tables[0])
 
             # For each higher temperature, add cross sections to the existing table
@@ -119,9 +125,10 @@ def main():
     if args.photon is not None:
         lib = openmc.data.ace.Library(args.photon)
 
+        tracker = ProgressTracker(len(lib.tables))
         for table in lib.tables:
             # Convert first temperature for the table
-            print(f'Converting: {table.name}')
+            tracker.starting(table.name)
             data = openmc.data.IncidentPhoton.from_ace(table)
 
             # Export HDF5 file
diff --git a/src/openmc_data/convert/convert_mcnp71.py b/src/openmc_data/convert/convert_mcnp71.py
index bcef339..2f393c1 100755
--- a/src/openmc_data/convert/convert_mcnp71.py
+++ b/src/openmc_data/convert/convert_mcnp71.py
@@ -15,6 +15,8 @@
 
 import openmc.data
 
+from openmc_data import ProgressTracker
+
 
 # Make sure Python version is sufficient
 assert sys.version_info >= (3, 6), "Python 3.6+ is required"
@@ -87,10 +89,12 @@ def main():
 
     library = openmc.data.DataLibrary()
 
-    for name, paths in sorted(tables.items()):
+    sorted_tables = sorted(tables.items())
+    tracker = ProgressTracker(len(sorted_tables))
+    for name, paths in sorted_tables:
         # Convert first temperature for the table
         p = paths[0]
-        print(f'Converting: {p}')
+        tracker.starting(p)
         if p.name.endswith('t'):
             data = openmc.data.ThermalScattering.from_ace(p)
         else:
@@ -116,9 +120,10 @@ def main():
     if args.photon is not None:
         lib = openmc.data.ace.Library(args.photon)
 
+        tracker = ProgressTracker(len(lib.tables))
         for table in lib.tables:
             # Convert first temperature for the table
-            print(f'Converting: {table.name}')
+            tracker.starting(table.name)
             data = openmc.data.IncidentPhoton.from_ace(table)
 
             # Export HDF5 file
diff --git a/src/openmc_data/convert/convert_tendl.py b/src/openmc_data/convert/convert_tendl.py
index 3b3ac34..c0e3f56 100755
--- a/src/openmc_data/convert/convert_tendl.py
+++ b/src/openmc_data/convert/convert_tendl.py
@@ -11,7 +11,7 @@
 from urllib.parse import urljoin
 
 import openmc.data
-from openmc_data import download, extract, calculate_download_size, all_release_details, get_file_types
+from openmc_data import download, extract, calculate_download_size, all_release_details, get_file_types, ProgressTracker
 
 
 # Make sure Python version is sufficient
@@ -139,7 +139,9 @@ def main():
 
     library = openmc.data.DataLibrary()
 
-    for filename in sorted(neutron_files):
+    neutron_files = sorted(neutron_files)
+    tracker = ProgressTracker(len(neutron_files))
+    for filename in neutron_files:
 
         # this is a fix for the TENDL-2017 release where the B10 ACE file which has an error on one of the values
         if args.release == "2017" and filename.name == "B010":
@@ -150,7 +152,7 @@ def main():
                 text = "".join(text[:423]) + "86896" + "".join(text[428:])
                 open(filename, "w").write(text)
 
-        print(f"Converting: {filename}")
+        tracker.starting(filename)
         data = openmc.data.IncidentNeutron.from_ace(filename)
 
         # Export HDF5 file
diff --git a/src/openmc_data/generate/generate_cendl.py b/src/openmc_data/generate/generate_cendl.py
index 7581e4f..a0ff41f 100755
--- a/src/openmc_data/generate/generate_cendl.py
+++ b/src/openmc_data/generate/generate_cendl.py
@@ -11,7 +11,7 @@
 from urllib.parse import urljoin
 
 import openmc.data
-from openmc_data import download, extract, process_neutron, state_download_size
+from openmc_data import download, extract, process_neutron, state_download_size, ProgressTracker
 
 
 class CustomFormatter(argparse.ArgumentDefaultsHelpFormatter,
@@ -123,7 +123,9 @@ def main():
 
     with Pool() as pool:
         results = []
-        for filename in sorted(neutron_files):
+        neutron_files = sorted(neutron_files)
+        tracker = ProgressTracker(len(neutron_files), verb='Processed')
+        for filename in neutron_files:
 
             # this is a fix for the CENDL 3.1 release where the
             # 22-Ti-047.C31 and 5-B-010.C31 files contain non-ASCII characters
@@ -137,7 +139,11 @@ def main():
                 open(filename, 'w').write('\r\n'.join(text))
 
             func_args = (filename, args.destination, args.libver)
-            r = pool.apply_async(process_neutron, func_args)
+            r = pool.apply_async(
+                process_neutron, func_args,
+                callback=tracker.callback(filename.name),
+                error_callback=tracker.callback(filename.name),
+            )
             results.append(r)
 
         for r in results:
diff --git a/src/openmc_data/generate/generate_endf.py b/src/openmc_data/generate/generate_endf.py
index a053acf..2b2406d 100755
--- a/src/openmc_data/generate/generate_endf.py
+++ b/src/openmc_data/generate/generate_endf.py
@@ -16,7 +16,7 @@
 from shutil import rmtree, copy, copyfileobj
 
 import openmc.data
-from openmc_data import download, process_neutron, process_thermal, state_download_size
+from openmc_data import download, process_neutron, process_thermal, state_download_size, ProgressTracker
 
 # Make sure Python version is sufficient
 assert sys.version_info >= (3, 6), "Python 3.6+ is required"
@@ -442,21 +442,29 @@ def main():
         with Pool() as pool:
             details = release_details[args.release][particle]
             results = []
-            for filename in details['endf_files']:
-
-                # Skip neutron evaluation that fails the processing stage
-                if filename.name == 'n-000_n_001.endf':
-                    continue
-
+            # Skip neutron evaluation that fails the processing stage
+            endf_files = [f for f in details['endf_files']
+                          if f.name != 'n-000_n_001.endf']
+            tracker = ProgressTracker(
+                len(endf_files) + len(details['sab_files']), verb='Processed')
+            for filename in endf_files:
                 func_args = (filename, args.destination / particle, args.libver,
                             args.temperatures)
-                r = pool.apply_async(process_neutron, func_args)
+                r = pool.apply_async(
+                    process_neutron, func_args,
+                    callback=tracker.callback(filename.name),
+                    error_callback=tracker.callback(filename.name),
+                )
                 results.append(r)
 
             for path_neutron, path_thermal in details['sab_files']:
                 func_args = (path_neutron, path_thermal,
                             args.destination / particle, args.libver)
-                r = pool.apply_async(process_thermal, func_args)
+                r = pool.apply_async(
+                    process_thermal, func_args,
+                    callback=tracker.callback(path_thermal.name),
+                    error_callback=tracker.callback(path_thermal.name),
+                )
                 results.append(r)
 
             for r in results:
@@ -472,10 +480,12 @@ def main():
     if 'photon' in args.particles:
         particle = 'photon'
         details = release_details[args.release][particle]
-        for photo_path, atom_path in zip(sorted(details['photo_files']),
-                                        sorted(details['atom_files'])):
+        photon_pairs = list(zip(sorted(details['photo_files']),
+                                sorted(details['atom_files'])))
+        tracker = ProgressTracker(len(photon_pairs))
+        for photo_path, atom_path in photon_pairs:
             # Generate instance of IncidentPhoton
-            print('Converting:', photo_path.name, atom_path.name)
+            tracker.starting(f'{photo_path.name} {atom_path.name}')
             data = openmc.data.IncidentPhoton.from_endf(photo_path, atom_path)
 
             # Export HDF5 file
diff --git a/src/openmc_data/generate/generate_fendl.py b/src/openmc_data/generate/generate_fendl.py
index a9cc317..4945d33 100644
--- a/src/openmc_data/generate/generate_fendl.py
+++ b/src/openmc_data/generate/generate_fendl.py
@@ -12,7 +12,7 @@
 from urllib.parse import urljoin
 
 import openmc.data
-from openmc_data import download, extract, process_neutron, state_download_size, all_release_details
+from openmc_data import download, extract, process_neutron, state_download_size, all_release_details, ProgressTracker
 
 
 class CustomFormatter(argparse.ArgumentDefaultsHelpFormatter,
@@ -104,9 +104,15 @@ def main():
 
     with Pool() as pool:
         results = []
-        for filename in sorted(neutron_files):
+        neutron_files = sorted(neutron_files)
+        tracker = ProgressTracker(len(neutron_files), verb='Processed')
+        for filename in neutron_files:
             func_args = (filename, args.destination, args.libver)
-            r = pool.apply_async(process_neutron, func_args)
+            r = pool.apply_async(
+                process_neutron, func_args,
+                callback=tracker.callback(filename.name),
+                error_callback=tracker.callback(filename.name),
+            )
             results.append(r)
 
         for r in results:
diff --git a/src/openmc_data/generate/generate_jeff33.py b/src/openmc_data/generate/generate_jeff33.py
index 43c4e8a..5828c5c 100755
--- a/src/openmc_data/generate/generate_jeff33.py
+++ b/src/openmc_data/generate/generate_jeff33.py
@@ -20,7 +20,7 @@
 
 import openmc.data
 
-from openmc_data import download, process_neutron, process_thermal
+from openmc_data import download, process_neutron, process_thermal, ProgressTracker
 
 # Make sure Python version is sufficient
 assert sys.version_info >= (3, 6), "Python 3.6+ is required"
@@ -162,15 +162,25 @@ def main():
         # PROCESS INCIDENT NEUTRON AND THERMAL SCATTERING DATA IN PARALLEL
 
         with Pool() as pool:
-            neutron_paths = neutron_dir.glob('*.jeff33')
+            neutron_paths = sorted(neutron_dir.glob('*.jeff33'))
             results = []
+            tracker = ProgressTracker(
+                len(neutron_paths) + len(thermal_paths), verb='Processed')
             for p in neutron_paths:
                 func_args = (p, destination, args.libver, args.temperatures)
-                r = pool.apply_async(process_neutron, func_args)
+                r = pool.apply_async(
+                    process_neutron, func_args,
+                    callback=tracker.callback(p.name),
+                    error_callback=tracker.callback(p.name),
+                )
                 results.append(r)
             for p_neut, p_therm in thermal_paths:
                 func_args = (p_neut, p_therm, destination, args.libver)
-                r = pool.apply_async(process_thermal, func_args)
+                r = pool.apply_async(
+                    process_thermal, func_args,
+                    callback=tracker.callback(p_therm.name),
+                    error_callback=tracker.callback(p_therm.name),
+                )
                 results.append(r)
             for r in results:
                 r.wait()
diff --git a/src/openmc_data/generate/generate_jendl.py b/src/openmc_data/generate/generate_jendl.py
index 2736830..e1a062c 100755
--- a/src/openmc_data/generate/generate_jendl.py
+++ b/src/openmc_data/generate/generate_jendl.py
@@ -12,7 +12,7 @@
 from urllib.parse import urljoin
 
 import openmc.data
-from openmc_data import download, extract, process_neutron, state_download_size, all_release_details
+from openmc_data import download, extract, process_neutron, state_download_size, all_release_details, ProgressTracker
 
 
 class CustomFormatter(argparse.ArgumentDefaultsHelpFormatter,
@@ -111,9 +111,15 @@ def main():
 
     with Pool() as pool:
         results = []
-        for filename in sorted(neutron_files):
+        neutron_files = sorted(neutron_files)
+        tracker = ProgressTracker(len(neutron_files), verb='Processed')
+        for filename in neutron_files:
             func_args = (filename, args.destination, args.libver, args.temperatures)
-            r = pool.apply_async(process_neutron, func_args)
+            r = pool.apply_async(
+                process_neutron, func_args,
+                callback=tracker.callback(filename.name),
+                error_callback=tracker.callback(filename.name),
+            )
             results.append(r)
 
         for r in results:
diff --git a/src/openmc_data/generate/generate_tendl.py b/src/openmc_data/generate/generate_tendl.py
index e122673..c7edf74 100644
--- a/src/openmc_data/generate/generate_tendl.py
+++ b/src/openmc_data/generate/generate_tendl.py
@@ -12,7 +12,7 @@
 from urllib.parse import urljoin
 
 import openmc.data
-from openmc_data import download, extract, process_neutron, state_download_size, all_release_details
+from openmc_data import download, extract, process_neutron, state_download_size, all_release_details, ProgressTracker
 
 
 class CustomFormatter(argparse.ArgumentDefaultsHelpFormatter,
@@ -141,9 +141,14 @@ def endf_to_h5_name(endf_filename):
 
     with Pool() as pool:
         results = []
+        tracker = ProgressTracker(len(neutron_files_to_process), verb='Processed')
         for filename in neutron_files_to_process:
             func_args = (filename, args.destination, args.libver)
-            r = pool.apply_async(process_neutron, func_args)
+            r = pool.apply_async(
+                process_neutron, func_args,
+                callback=tracker.callback(filename.name),
+                error_callback=tracker.callback(filename.name),
+            )
             results.append(r)
 
         for r in results:
diff --git a/src/openmc_data/utils.py b/src/openmc_data/utils.py
index d5684b3..44eebd9 100644
--- a/src/openmc_data/utils.py
+++ b/src/openmc_data/utils.py
@@ -1,6 +1,8 @@
 import hashlib
 import shutil
 import tarfile
+import threading
+import time
 from typing import Iterable
 import warnings
 import zipfile
@@ -18,6 +20,75 @@
 _BLOCK_SIZE = 16384
 
 
+def format_duration(seconds):
+    """Format a number of seconds as a ``H:MM:SS`` string."""
+    if seconds is None or seconds != seconds:  # None or NaN
+        return '--:--:--'
+    seconds = int(round(seconds))
+    hours, remainder = divmod(seconds, 3600)
+    minutes, secs = divmod(remainder, 60)
+    return f'{hours:d}:{minutes:02d}:{secs:02d}'
+
+
+class ProgressTracker:
+    """Track progress through a fixed number of items and estimate the time
+    remaining.
+
+    The estimate is a simple extrapolation from the average time taken per
+    completed item so far. Use :meth:`starting` for serial loops (call it just
+    before processing each item) and :meth:`callback` with a
+    ``multiprocessing.Pool`` (pass the returned function as the ``apply_async``
+    callback so progress is reported as each item completes).
+
+    Parameters
+    ----------
+    total : int
+        Total number of items that will be processed.
+    verb : str
+        Word printed at the start of each progress line, e.g. ``'Converting'``.
+    """
+
+    def __init__(self, total, verb='Converting'):
+        self.total = max(int(total), 0)
+        self.verb = verb
+        self.count = 0
+        self.start = time.monotonic()
+        self._lock = threading.Lock()
+
+    def _format(self, position, completed, name):
+        elapsed = time.monotonic() - self.start
+        eta = elapsed / completed * (self.total - completed) if completed > 0 else None
+        pct = 100 * position / self.total if self.total else 100
+        line = (f'{self.verb} [{position}/{self.total} {pct:3.0f}%] '
+                f'elapsed {format_duration(elapsed)} ETA {format_duration(eta)}')
+        return f'{line}: {name}' if name else line
+
+    def starting(self, name=''):
+        """Print a progress line for an item that is about to be processed.
+
+        The ETA is based on the items completed before this one, which is the
+        appropriate estimate for a serial loop.
+        """
+        with self._lock:
+            self.count += 1
+            line = self._format(self.count, self.count - 1, name)
+        print(line, flush=True)
+
+    def complete(self, name=''):
+        """Advance the counter and print a progress line for a finished item."""
+        with self._lock:
+            self.count += 1
+            line = self._format(self.count, self.count, name)
+        print(line, flush=True)
+
+    def callback(self, name=''):
+        """Return a one-argument function suitable as an ``apply_async``
+        ``callback`` / ``error_callback`` that reports completion of ``name``."""
+        def _callback(_result=None):
+            self.complete(name)
+        return _callback
+
+
 def _require_openmc():
     if openmc is None:
         raise ModuleNotFoundError(