diff --git a/include/fast_float/float_common.h b/include/fast_float/float_common.h
index 4a290f4..a96c9cc 100644
--- a/include/fast_float/float_common.h
+++ b/include/fast_float/float_common.h
@@ -530,7 +530,7 @@ inline constexpr int binary_format<double>::smallest_power_of_ten() {
 }
 template <>
 inline constexpr int binary_format<float>::smallest_power_of_ten() {
-  return -65;
+  return -64;
 }
 
 template <> inline constexpr size_t binary_format<double>::max_digits() {