diff --git a/mz_zip.c b/mz_zip.c
index 139a874b..ca505381 100644
--- a/mz_zip.c
+++ b/mz_zip.c
@@ -2663,7 +2663,7 @@ static void mz_zip_dosdate_to_raw_tm(uint64_t dos_date, struct tm *ptm) {
     uint64_t date = (uint64_t)(dos_date >> 16);
 
     ptm->tm_mday = (uint16_t)(date & 0x1f);
-    ptm->tm_mon = (uint16_t)(((date & 0x1E0) / 0x20) - 1);
+    ptm->tm_mon = (uint16_t)((date & 0x1E0) / 0x20) - 1;
     ptm->tm_year = (uint16_t)(((date & 0x0FE00) / 0x0200) + 80);
     ptm->tm_hour = (uint16_t)((dos_date & 0xF800) / 0x800);
     ptm->tm_min = (uint16_t)((dos_date & 0x7E0) / 0x20);