diff --git a/chprintf.c b/chprintf.c
index 6484fa2..2b9bb62 100644
--- a/chprintf.c
+++ b/chprintf.c
@@ -205,8 +205,10 @@ static char *ftoaS(char *p, float num, int precision) {
     precision=0;
   p=ftoa(p, num, precision);
   // remove zeros at end
-  while (p[-1]=='0') p--;
-  if (p[-1]=='.') p--;
+  if (precision){
+    while (p[-1]=='0') p--;
+    if (p[-1]=='.') p--;
+  }
   if (prefix)
     *p++ = prefix;
   return p;