diff --git a/src/CalcManager/Ratpack/num.cpp b/src/CalcManager/Ratpack/num.cpp
index 67fd54f5..56857e80 100644
--- a/src/CalcManager/Ratpack/num.cpp
+++ b/src/CalcManager/Ratpack/num.cpp
@@ -601,7 +601,7 @@ bool zernum(_In_ PNUMBER a)
 
     // loop over all the digits until you find a nonzero or until you run
     // out of digits
-    for (int32_t length = a->cdigit; length > 0; --length)
+    for (auto length = a->cdigit; length > 0; --length)
     {
         if (*pcha)
         {