diff --git a/libr/hash/calc.c b/libr/hash/calc.c
index f79df735d8..a2ea6c8de4 100644
--- a/libr/hash/calc.c
+++ b/libr/hash/calc.c
@@ -14,7 +14,7 @@ static int bitnum(int bit) {
 /* TODO: do it more beautiful with structs and not spaguetis */
 /* TODO: find a better method name */
 R_API int r_hash_calculate(RHash *ctx, int algobit, const ut8 *buf, int len) {
-	if (len<0)
+	if (len <= 0)
 		return 0;
 	if (algobit & R_HASH_MD4) {
 		r_hash_do_md4 (ctx, buf, len);