diff --git a/include/boost/json/basic_parser_impl.hpp b/include/boost/json/basic_parser_impl.hpp
index 071a224c9..13ce2c87b 100644
--- a/include/boost/json/basic_parser_impl.hpp
+++ b/include/boost/json/basic_parser_impl.hpp
@@ -155,6 +155,11 @@ dec_to_float(
     if(neg)
         x = -x;
 
+    // pow10 returns infinity for large exponents,
+    // and zero times infinity is NaN
+    if(m == 0)
+        return x;
+
     if(e < -305)
     {
         x *= 1e-305 ;
diff --git a/test/double.cpp b/test/double.cpp
index 0b13c7f8e..bc657ee2b 100644
--- a/test/double.cpp
+++ b/test/double.cpp
@@ -315,6 +315,8 @@ class double_test
         grind_double("-0.010", -0.01);
         grind_double("-0.0", -0.0);
         grind_double("-0e0", -0.0);
+        grind_double( "0e400",  0.0);
+        grind_double("-0e400", -0.0);
         grind_double( "18.4",  18.4);
         grind_double("-18.4", -18.4);
         grind_double( "18446744073709551616",  1.8446744073709552e+19);