1 files changed, 3 insertions, 2 deletions
diff --git a/py/mpz.h b/py/mpz.h
index b00d2b6555..e287cdd105 100644
--- a/py/mpz.h
+++ b/py/mpz.h
@@ -78,8 +78,9 @@ typedef int8_t mpz_dbl_dig_signed_t;
   #define MPZ_LONG_1 1L
 #endif
 
-#define MPZ_NUM_DIG_FOR_INT (sizeof(mp_int_t) * 8 / MPZ_DIG_SIZE + 1)
-#define MPZ_NUM_DIG_FOR_LL (sizeof(long long) * 8 / MPZ_DIG_SIZE + 1)
+// these define the maximum storage needed to hold an int or long long
+#define MPZ_NUM_DIG_FOR_INT ((sizeof(mp_int_t) * 8 + MPZ_DIG_SIZE - 1) / MPZ_DIG_SIZE)
+#define MPZ_NUM_DIG_FOR_LL ((sizeof(long long) * 8 + MPZ_DIG_SIZE - 1) / MPZ_DIG_SIZE)
 
 typedef struct _mpz_t {
     mp_uint_t neg : 1;