diff --git a/src/main/java/net/openhft/chronicle/map/serialization/SizeMarshallers.java b/src/main/java/net/openhft/chronicle/map/serialization/SizeMarshallers.java
index d5fdbc810..dfb79af4d 100644
--- a/src/main/java/net/openhft/chronicle/map/serialization/SizeMarshallers.java
+++ b/src/main/java/net/openhft/chronicle/map/serialization/SizeMarshallers.java
@@ -18,6 +18,8 @@ package net.openhft.chronicle.map.serialization;
 
 import net.openhft.lang.io.Bytes;
 
+import static net.openhft.lang.io.IOTools.stopBitLength;
+
 public final class SizeMarshallers {
 
     public static SizeMarshaller stopBit() {
@@ -29,11 +31,7 @@ public final class SizeMarshallers {
 
         @Override
         public int sizeEncodingSize(long size) {
-            if (size <= 127)
-                return 1;
-            // numberOfLeadingZeros is cheap intrinsic on modern CPUs
-            // integral division is not... but there is no choice
-            return ((70 - Long.numberOfLeadingZeros(size)) / 7);
+            return stopBitLength(size);
         }
 
         @Override