diff --git a/crypto/ecdsa/ecdsa_test.cc b/crypto/ecdsa/ecdsa_test.cc
index 26f606f..bef91c9 100644
--- a/crypto/ecdsa/ecdsa_test.cc
+++ b/crypto/ecdsa/ecdsa_test.cc
@@ -340,15 +340,19 @@
   return true;
 }
 
+static size_t BitsToBytes(size_t bits) {
+  return (bits / 8) + (7 + (bits % 8)) / 8;
+}
+
 int main(void) {
   CRYPTO_library_init();
 
   if (!TestBuiltin(stdout) ||
-      !TestECDSA_SIG_max_len(224/8) ||
-      !TestECDSA_SIG_max_len(256/8) ||
-      !TestECDSA_SIG_max_len(384/8) ||
-      !TestECDSA_SIG_max_len(512/8) ||
-      !TestECDSA_SIG_max_len(10000)) {
+      !TestECDSA_SIG_max_len(BitsToBytes(224)) ||
+      !TestECDSA_SIG_max_len(BitsToBytes(256)) ||
+      !TestECDSA_SIG_max_len(BitsToBytes(384)) ||
+      !TestECDSA_SIG_max_len(BitsToBytes(521)) ||
+      !TestECDSA_SIG_max_len(BitsToBytes(10000))) {
     printf("\nECDSA test failed\n");
     ERR_print_errors_fp(stdout);
     return 1;