diff --git a/src/libraries/System.Private.CoreLib/src/System/Buffers/Text/Utf8Formatter/FormattingHelpers.cs b/src/libraries/System.Private.CoreLib/src/System/Buffers/Text/Utf8Formatter/FormattingHelpers.cs
index 6316a19b33559e..991ba2448451c7 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Buffers/Text/Utf8Formatter/FormattingHelpers.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Buffers/Text/Utf8Formatter/FormattingHelpers.cs
@@ -33,19 +33,6 @@ public static char GetSymbolOrDefault(in StandardFormat format, char defaultSymb
 
         #region UTF-8 Helper methods
 
-        /// <summary>
-        /// Fills a buffer with the ASCII character '0' (0x30).
-        /// </summary>
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static void FillWithAsciiZeros(Span<byte> buffer)
-        {
-            // This is a faster implementation of Span<T>.Fill().
-            for (int i = 0; i < buffer.Length; i++)
-            {
-                buffer[i] = (byte)'0';
-            }
-        }
-
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static void WriteDigits(ulong value, Span<byte> buffer)
         {
diff --git a/src/libraries/System.Private.CoreLib/src/System/Buffers/Text/Utf8Formatter/Utf8Formatter.Integer.Unsigned.D.cs b/src/libraries/System.Private.CoreLib/src/System/Buffers/Text/Utf8Formatter/Utf8Formatter.Integer.Unsigned.D.cs
index 2a2059674f9163..c449b3341af840 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Buffers/Text/Utf8Formatter/Utf8Formatter.Integer.Unsigned.D.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Buffers/Text/Utf8Formatter/Utf8Formatter.Integer.Unsigned.D.cs
@@ -43,7 +43,8 @@ private static bool TryFormatUInt64D(ulong value, byte precision, Span<byte> des
 
             if (leadingZeroCount > 0)
             {
-                FormattingHelpers.FillWithAsciiZeros(destination.Slice(0, leadingZeroCount));
+                // Fill with ASCII zeros
+                destination.Slice(0, leadingZeroCount).Fill((byte)'0');
             }
             FormattingHelpers.WriteDigits(value, destination.Slice(leadingZeroCount, digitCount));
 
diff --git a/src/libraries/System.Private.CoreLib/src/System/Buffers/Text/Utf8Formatter/Utf8Formatter.Integer.Unsigned.N.cs b/src/libraries/System.Private.CoreLib/src/System/Buffers/Text/Utf8Formatter/Utf8Formatter.Integer.Unsigned.N.cs
index c7f564ae6c9f60..f28935a197758d 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Buffers/Text/Utf8Formatter/Utf8Formatter.Integer.Unsigned.N.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Buffers/Text/Utf8Formatter/Utf8Formatter.Integer.Unsigned.N.cs
@@ -48,7 +48,9 @@ private static bool TryFormatUInt64N(ulong value, byte precision, Span<byte> des
             if (trailingZeroCount > 0)
             {
                 destination[digitCount + commaCount] = Utf8Constants.Period;
-                FormattingHelpers.FillWithAsciiZeros(destination.Slice(digitCount + commaCount + 1, trailingZeroCount));
+
+                // Fill with ASCII zeros
+                destination.Slice(digitCount + commaCount + 1, trailingZeroCount).Fill((byte)'0');
             }
 
             return true;