diff --git a/itoa.comma.h b/itoa.comma.h
new file mode 100644
index 0000000..680c679
--- /dev/null
+++ b/itoa.comma.h
@@ -0,0 +1,49 @@
+/**
+ @param  {uint64_t}  x        - Number to convert to comma delimited string
+ @param  {char*}    [output_] - Optional buffer to copy output to
+ @return {char*} Returns pointer to comma delimited NULL terminated string
+ @notes          Does NOT NULL terminate the output_ string (to allow for string concatenation)
+ @history
+    version 9 - Renamed p,e to dst, end
+    Version 8 - Cleanup notes
+    Version 7 - cleanup 'x > 9' to 'x > 0'
+    Version 6 - Add jsdoc
+    Verison 5 - add optional output, does NOT null terminate output
+    Version 4 - document hard-coded max string length 32
+    Version 3 - cleanup '>= 10' to '> 9'
+    Verison 2 - add 4 buffers
+    Version 1 - initial implementation
+*/
+const char*
+itoa_comma( uint64_t x, char *output_ = NULL )
+{
+    const  int     MAX_CHARS   = 31; // 2^32 - 1 =              4,294,967,295 = 13 chars
+    const  int     NUM_BUFFERS =  4; // 2^64 - 1 = 18,446,744,073,709,551,615 = 26 chars
+
+    static char    aString[ NUM_BUFFERS ][ MAX_CHARS+1 ];
+    static uint8_t iString     = 0;
+   
+    char *dst = &aString[ iString ][ MAX_CHARS ];
+    char *end = dst; // save copy of end pointer
+
+    *dst-- = 0;
+    while( x > 999 )
+    {
+        *dst-- = '0' + (x % 10); x /= 10;
+        *dst-- = '0' + (x % 10); x /= 10;
+        *dst-- = '0' + (x % 10); x /= 10;
+        *dst-- = ',';
+    }
+
+    /*      */ { *dst-- = '0' + (x % 10); x /= 10; }
+    if (x > 0) { *dst-- = '0' + (x % 10); x /= 10; }
+    if (x > 0) { *dst-- = '0' + (x % 10); x /= 10; }
+
+    iString++;
+    iString &= (NUM_BUFFERS-1);
+
+    if( output_ )
+        memcpy( output_, dst+1, end-dst-1 ); // -1 to NOT include NULL terminator
+
+    return ++dst;
+}