diff --git a/include/fmt/chrono.h b/include/fmt/chrono.h
index e4bc1ce4fd45..46590074b823 100644
--- a/include/fmt/chrono.h
+++ b/include/fmt/chrono.h
@@ -934,10 +934,9 @@ inline auto to_nonnegative_int(T value, Int upper) -> Int {
 }
 template <typename T, typename Int, FMT_ENABLE_IF(!std::is_integral<T>::value)>
 inline auto to_nonnegative_int(T value, Int upper) -> Int {
-  auto int_value = static_cast<Int>(value);
-  if (int_value < 0 || value > static_cast<T>(upper))
+  if (value < 0 || value >= static_cast<T>(upper) + 1)
     FMT_THROW(format_error("invalid value"));
-  return int_value;
+  return static_cast<Int>(value);
 }
 
 constexpr auto pow10(std::uint32_t n) -> long long {
diff --git a/test/chrono-test.cc b/test/chrono-test.cc
index a915359807c1..b7a4e59a8d72 100644
--- a/test/chrono-test.cc
+++ b/test/chrono-test.cc
@@ -989,6 +989,9 @@ TEST(chrono_test, glibc_extensions) {
 TEST(chrono_test, out_of_range) {
   auto d = std::chrono::duration<unsigned long, std::giga>(538976288);
   EXPECT_THROW((void)fmt::format("{:%j}", d), fmt::format_error);
+  // A floating-point day count that doesn't fit in int.
+  auto fd = std::chrono::duration<double>(1e300);
+  EXPECT_THROW((void)fmt::format("{:%j}", fd), fmt::format_error);
 }
 
 TEST(chrono_test, year_month_day) {