diff --git a/modules/beast_crypto/math/UnsignedInteger.h b/modules/beast_crypto/math/UnsignedInteger.h
index 04f32a720..024d5c2b2 100644
--- a/modules/beast_crypto/math/UnsignedInteger.h
+++ b/modules/beast_crypto/math/UnsignedInteger.h
@@ -176,7 +176,7 @@ public:
     /** Determine if all bits are zero. */
     bool isZero () const
     {
-        for (int i = 0; i < Bytes; ++i)
+        for (int i = 0; i < CalcCount; ++i)
         {
             if (m_values [i] != 0)
                 return false;