diff --git a/juce_amalgamated.cpp b/juce_amalgamated.cpp
index 2217285426..fbb938a132 100644
--- a/juce_amalgamated.cpp
+++ b/juce_amalgamated.cpp
@@ -4510,7 +4510,7 @@ void MD5::ProcessContext::processBlock (const uint8* const data, size_t dataSize
 
 		i = spaceLeft;
 
-		while (i < dataSize - 63)
+		while (i + 64 <= dataSize)
 		{
 			transform (data + i);
 			i += 64;
diff --git a/src/cryptography/juce_MD5.cpp b/src/cryptography/juce_MD5.cpp
index db0a35b4b4..e7995f0bc9 100644
--- a/src/cryptography/juce_MD5.cpp
+++ b/src/cryptography/juce_MD5.cpp
@@ -163,7 +163,7 @@ void MD5::ProcessContext::processBlock (const uint8* const data, size_t dataSize
 
         i = spaceLeft;
 
-        while (i < dataSize - 63)
+        while (i + 64 <= dataSize)
         {
             transform (data + i);
             i += 64;