diff --git a/include/spdlog/details/file_helper.h b/include/spdlog/details/file_helper.h
index f7282000..8c1132d9 100644
--- a/include/spdlog/details/file_helper.h
+++ b/include/spdlog/details/file_helper.h
@@ -122,7 +122,7 @@ public:
     // ".mylog" => (".mylog". "")
     // "my_folder/.mylog" => ("my_folder/.mylog", "")
     // "my_folder/.mylog.txt" => ("my_folder/.mylog", ".txt")
-    static std::tuple<filename_t, filename_t> split_by_extenstion(const spdlog::filename_t &fname)
+    static std::tuple<filename_t, filename_t> split_by_extension(const spdlog::filename_t &fname)
     {
         auto ext_index = fname.rfind('.');
 
diff --git a/include/spdlog/sinks/daily_file_sink.h b/include/spdlog/sinks/daily_file_sink.h
index 376a1ab0..d20de442 100644
--- a/include/spdlog/sinks/daily_file_sink.h
+++ b/include/spdlog/sinks/daily_file_sink.h
@@ -32,7 +32,7 @@ struct daily_filename_calculator
     static filename_t calc_filename(const filename_t &filename, const tm &now_tm)
     {
         filename_t basename, ext;
-        std::tie(basename, ext) = details::file_helper::split_by_extenstion(filename);
+        std::tie(basename, ext) = details::file_helper::split_by_extension(filename);
         std::conditional<std::is_same<filename_t::value_type, char>::value, fmt::memory_buffer, fmt::wmemory_buffer>::type w;
         fmt::format_to(
             w, SPDLOG_FILENAME_T("{}_{:04d}-{:02d}-{:02d}{}"), basename, now_tm.tm_year + 1900, now_tm.tm_mon + 1, now_tm.tm_mday, ext);
diff --git a/include/spdlog/sinks/rotating_file_sink.h b/include/spdlog/sinks/rotating_file_sink.h
index ef210d83..73c377d4 100644
--- a/include/spdlog/sinks/rotating_file_sink.h
+++ b/include/spdlog/sinks/rotating_file_sink.h
@@ -48,7 +48,7 @@ public:
         if (index != 0u)
         {
             filename_t basename, ext;
-            std::tie(basename, ext) = details::file_helper::split_by_extenstion(filename);
+            std::tie(basename, ext) = details::file_helper::split_by_extension(filename);
             fmt::format_to(w, SPDLOG_FILENAME_T("{}.{}{}"), basename, index, ext);
         }
         else
diff --git a/tests/test_file_helper.cpp b/tests/test_file_helper.cpp
index ecdc5afe..073ef93a 100644
--- a/tests/test_file_helper.cpp
+++ b/tests/test_file_helper.cpp
@@ -81,12 +81,12 @@ static void test_split_ext(const char *fname, const char *expect_base, const cha
     std::replace(expected_base.begin(), expected_base.end(), '/', '\\');
 #endif
     spdlog::filename_t basename, ext;
-    std::tie(basename, ext) = file_helper::split_by_extenstion(filename);
+    std::tie(basename, ext) = file_helper::split_by_extension(filename);
     REQUIRE(basename == expected_base);
     REQUIRE(ext == expected_ext);
 }
 
-TEST_CASE("file_helper_split_by_extenstion", "[file_helper::split_by_extenstion()]]")
+TEST_CASE("file_helper_split_by_extension", "[file_helper::split_by_extension()]]")
 {
     test_split_ext("mylog.txt", "mylog", ".txt");
     test_split_ext(".mylog.txt", ".mylog", ".txt");