diff --git a/format.h b/format.h
index d29c080c..3674ac2d 100644
--- a/format.h
+++ b/format.h
@@ -1894,7 +1894,7 @@ class FormatInt {
 // a pointer to the end of the formatted string. This function doesn't
 // write a terminating null character.
 template <typename T>
-inline void FormatDec(char *&buffer, T value) {
+inline void format_decimal(char *&buffer, T value) {
   typename internal::IntTraits<T>::MainType abs_value = value;
   if (internal::is_negative(value)) {
     *buffer++ = '-';
diff --git a/test/format-test.cc b/test/format-test.cc
index 60779868..fb4d39f9 100644
--- a/test/format-test.cc
+++ b/test/format-test.cc
@@ -1455,27 +1455,28 @@ TEST(FormatIntTest, FormatInt) {
 }
 
 template <typename T>
-std::string FormatDec(T value) {
+std::string format_decimal(T value) {
   char buffer[10];
   char *ptr = buffer;
-  fmt::FormatDec(ptr, value);
+  fmt::format_decimal(ptr, value);
   return std::string(buffer, ptr);
 }
 
 TEST(FormatIntTest, FormatDec) {
-  EXPECT_EQ("-42", FormatDec(static_cast<char>(-42)));
-  EXPECT_EQ("-42", FormatDec(static_cast<short>(-42)));
+  EXPECT_EQ("-42", format_decimal(static_cast<char>(-42)));
+  EXPECT_EQ("-42", format_decimal(static_cast<short>(-42)));
   std::ostringstream os;
   os << std::numeric_limits<unsigned short>::max();
-  EXPECT_EQ(os.str(), FormatDec(std::numeric_limits<unsigned short>::max()));
-  EXPECT_EQ("1", FormatDec(1));
-  EXPECT_EQ("-1", FormatDec(-1));
-  EXPECT_EQ("42", FormatDec(42));
-  EXPECT_EQ("-42", FormatDec(-42));
-  EXPECT_EQ("42", FormatDec(42l));
-  EXPECT_EQ("42", FormatDec(42ul));
-  EXPECT_EQ("42", FormatDec(42ll));
-  EXPECT_EQ("42", FormatDec(42ull));
+  EXPECT_EQ(os.str(),
+            format_decimal(std::numeric_limits<unsigned short>::max()));
+  EXPECT_EQ("1", format_decimal(1));
+  EXPECT_EQ("-1", format_decimal(-1));
+  EXPECT_EQ("42", format_decimal(42));
+  EXPECT_EQ("-42", format_decimal(-42));
+  EXPECT_EQ("42", format_decimal(42l));
+  EXPECT_EQ("42", format_decimal(42ul));
+  EXPECT_EQ("42", format_decimal(42ll));
+  EXPECT_EQ("42", format_decimal(42ull));
 }
 
 TEST(FormatTest, Print) {