diff --git a/include/fmt/chrono.h b/include/fmt/chrono.h
index bf83ce00..f47f1758 100644
--- a/include/fmt/chrono.h
+++ b/include/fmt/chrono.h
@@ -676,12 +676,10 @@ enum class numeric_system {
 
 // Glibc extensions for formatting numeric values.
 enum class pad_type {
-  unspecified,
+  // Pad a numeric result string with zeros (the default).
+  zero,
   // Do not pad a numeric result string.
   none,
-  // Pad a numeric result string with zeros even if the conversion specifier
-  // character uses space-padding by default.
-  zero,
   // Pad a numeric result string with spaces.
   space,
 };
@@ -706,7 +704,7 @@ FMT_CONSTEXPR auto parse_chrono_format(const Char* begin, const Char* end,
   if (*begin != '%') FMT_THROW(format_error("invalid format"));
   auto ptr = begin;
   while (ptr != end) {
-    pad_type pad = pad_type::unspecified;
+    pad_type pad = pad_type::zero;
     auto c = *ptr;
     if (c == '}') break;
     if (c != '%') {
@@ -726,10 +724,6 @@ FMT_CONSTEXPR auto parse_chrono_format(const Char* begin, const Char* end,
       pad = pad_type::none;
       ++ptr;
       break;
-    case '0':
-      pad = pad_type::zero;
-      ++ptr;
-      break;
     }
     if (ptr == end) FMT_THROW(format_error("invalid format"));
     c = *ptr++;
@@ -1637,7 +1631,7 @@ class tm_writer {
   void on_iso_time() {
     on_24_hour_time();
     *out_++ = ':';
-    on_second(numeric_system::standard, pad_type::unspecified);
+    on_second(numeric_system::standard, pad_type::zero);
   }
 
   void on_am_pm() {
@@ -1878,7 +1872,7 @@ struct chrono_formatter {
     }
   }
 
-  void write(Rep value, int width, pad_type pad = pad_type::unspecified) {
+  void write(Rep value, int width, pad_type pad = pad_type::zero) {
     write_sign();
     if (isnan(value)) return write_nan();
     uint32_or_64_or_128_t<int> n =
@@ -2011,7 +2005,7 @@ struct chrono_formatter {
     on_24_hour_time();
     *out++ = ':';
     if (handle_nan_inf()) return;
-    on_second(numeric_system::standard, pad_type::unspecified);
+    on_second(numeric_system::standard, pad_type::zero);
   }
 
   void on_am_pm() {
@@ -2151,7 +2145,7 @@ struct formatter<day, Char> : private formatter<std::tm, Char> {
     detail::get_locale loc(false, ctx.locale());
     auto w = detail::tm_writer<decltype(ctx.out()), Char>(loc, ctx.out(), time);
     w.on_day_of_month(detail::numeric_system::standard,
-                      detail::pad_type::unspecified);
+                      detail::pad_type::zero);
     return w.out();
   }
 };
diff --git a/test/chrono-test.cc b/test/chrono-test.cc
index 0a70210d..5befcab6 100644
--- a/test/chrono-test.cc
+++ b/test/chrono-test.cc
@@ -971,13 +971,11 @@ TEST(chrono_test, glibc_extensions) {
                    std::chrono::seconds(3);
 
     EXPECT_EQ(fmt::format("{:%I,%H,%M,%S}", d), "01,01,02,03");
-    EXPECT_EQ(fmt::format("{:%0I,%0H,%0M,%0S}", d), "01,01,02,03");
     EXPECT_EQ(fmt::format("{:%_I,%_H,%_M,%_S}", d), " 1, 1, 2, 3");
     EXPECT_EQ(fmt::format("{:%-I,%-H,%-M,%-S}", d), "1,1,2,3");
     EXPECT_EQ(fmt::format("{:%-I,%H,%M,%S}", d), "1,01,02,03");
 
     EXPECT_EQ(fmt::format("{:%OI,%OH,%OM,%OS}", d), "01,01,02,03");
-    EXPECT_EQ(fmt::format("{:%0OI,%0OH,%0OM,%0OS}", d), "01,01,02,03");
     EXPECT_EQ(fmt::format("{:%_OI,%_OH,%_OM,%_OS}", d), " 1, 1, 2, 3");
     EXPECT_EQ(fmt::format("{:%-OI,%-OH,%-OM,%-OS}", d), "1,1,2,3");
   }
@@ -985,12 +983,10 @@ TEST(chrono_test, glibc_extensions) {
   {
     const auto tm = make_tm(1970, 1, 1, 1, 2, 3);
     EXPECT_EQ(fmt::format("{:%I,%H,%M,%S}", tm), "01,01,02,03");
-    EXPECT_EQ(fmt::format("{:%0I,%0H,%0M,%0S}", tm), "01,01,02,03");
     EXPECT_EQ(fmt::format("{:%_I,%_H,%_M,%_S}", tm), " 1, 1, 2, 3");
     EXPECT_EQ(fmt::format("{:%-I,%-H,%-M,%-S}", tm), "1,1,2,3");
 
     EXPECT_EQ(fmt::format("{:%OI,%OH,%OM,%OS}", tm), "01,01,02,03");
-    EXPECT_EQ(fmt::format("{:%0OI,%0OH,%0OM,%0OS}", tm), "01,01,02,03");
     EXPECT_EQ(fmt::format("{:%_OI,%_OH,%_OM,%_OS}", tm), " 1, 1, 2, 3");
     EXPECT_EQ(fmt::format("{:%-OI,%-OH,%-OM,%-OS}", tm), "1,1,2,3");
   }
@@ -998,7 +994,6 @@ TEST(chrono_test, glibc_extensions) {
   {
     const auto d = std::chrono::seconds(3) + std::chrono::milliseconds(140);
     EXPECT_EQ(fmt::format("{:%S}", d), "03.140");
-    EXPECT_EQ(fmt::format("{:%0S}", d), "03.140");
     EXPECT_EQ(fmt::format("{:%_S}", d), " 3.140");
     EXPECT_EQ(fmt::format("{:%-S}", d), "3.140");
   }
@@ -1006,7 +1001,6 @@ TEST(chrono_test, glibc_extensions) {
   {
     auto d = std::chrono::duration<double>(3.14);
     EXPECT_EQ(fmt::format("{:%S}", d), "03.140000");
-    EXPECT_EQ(fmt::format("{:%0S}", d), "03.140000");
     EXPECT_EQ(fmt::format("{:%_S}", d), " 3.140000");
     EXPECT_EQ(fmt::format("{:%-S}", d), "3.140000");
   }
@@ -1015,7 +1009,6 @@ TEST(chrono_test, glibc_extensions) {
     auto t = std::tm();
     t.tm_yday = 7;
     EXPECT_EQ(fmt::format("{:%U,%W,%V}", t), "02,01,01");
-    EXPECT_EQ(fmt::format("{:%0U,%0W,%0V}", t), "02,01,01");
     EXPECT_EQ(fmt::format("{:%_U,%_W,%_V}", t), " 2, 1, 1");
     EXPECT_EQ(fmt::format("{:%-U,%-W,%-V}", t), "2,1,1");
   }
@@ -1024,7 +1017,6 @@ TEST(chrono_test, glibc_extensions) {
     auto t = std::tm();
     t.tm_mday = 7;
     EXPECT_EQ(fmt::format("{:%d}", t), "07");
-    EXPECT_EQ(fmt::format("{:%0d}", t), "07");
     EXPECT_EQ(fmt::format("{:%_d}", t), " 7");
     EXPECT_EQ(fmt::format("{:%-d}", t), "7");