diff --git a/git-compat-util.h b/git-compat-util.h
index dcc786edaa..acef7f6bcb 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -981,11 +981,9 @@ static inline char *xstrdup_or_null(const char *str)
 
 static inline size_t xsize_t(off_t len)
 {
-	size_t size = (size_t) len;
-
-	if (len != (off_t) size)
+	if (len < 0 || (uintmax_t) len > SIZE_MAX)
 		die("Cannot handle files this big");
-	return size;
+	return (size_t) len;
 }
 
 __attribute__((format (printf, 3, 4)))