diff --git a/src/index.spec.ts b/src/index.spec.ts
index e962ffe..17a6a40 100644
--- a/src/index.spec.ts
+++ b/src/index.spec.ts
@@ -212,6 +212,18 @@ describe("parse(len, str)", () => {
     });
   });
 
+  it("should parse str with tab whitespace", () => {
+    var range = parse(1000, "bytes=\t40-80,\t81-90\t,-1\t");
+    expect(range).toEqual({
+      type: "bytes",
+      ranges: [
+        { start: 40, end: 80 },
+        { start: 81, end: 90 },
+        { start: 999, end: 999 },
+      ],
+    });
+  });
+
   it("should parse non-byte range", () => {
     var range = parse(1000, "items=0-5");
     expect(range).toEqual({
diff --git a/src/index.ts b/src/index.ts
index 8640bea..d5b18f9 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -51,8 +51,8 @@ export function parse(size: number, str: string): Result | -1 | -2 {
     // handle ows around numbers
     let startStrIndex = index;
     let endStrIndex = endIndex;
-    while (str.charCodeAt(startStrIndex) === 32) startStrIndex++;
-    while (str.charCodeAt(endStrIndex - 1) === 32) endStrIndex--;
+    while (isOws(str.charCodeAt(startStrIndex))) startStrIndex++;
+    while (isOws(str.charCodeAt(endStrIndex - 1))) endStrIndex--;
 
     let start = NaN;
     let end = NaN;
@@ -103,6 +103,13 @@ export function parse(size: number, str: string): Result | -1 | -2 {
   return { type, ranges };
 }
 
+/**
+ * Check for optional whitespace (SP / HTAB), RFC 9110 section 5.6.3.
+ */
+function isOws(code: number): boolean {
+  return code === 32 || code === 9;
+}
+
 /**
  * Parse string to integer.
  */