diff --git a/src/timeconv.c b/src/timeconv.c
index ba9b4c8..f169ede 100644
--- a/src/timeconv.c
+++ b/src/timeconv.c
@@ -1,51 +1,51 @@
 #include "define.h"
 
 
 
 char* pst_fileTimeToAscii(const FILETIME* filetime, char* result) {
     time_t t;
     t = pst_fileTimeToUnixTime(filetime);
     return ctime_r(&t, result);
 }
 
 size_t pst_fileTimeToString(const FILETIME* filetime, const char* date_format, char* result) {
     time_t t;
     t = pst_fileTimeToUnixTime(filetime);
     return strftime(result, MAXDATEFMTLEN-1, date_format, localtime(&t));
 }
 
 
 void pst_fileTimeToStructTM(const FILETIME *filetime, struct tm *result) {
     time_t t1;
     t1 = pst_fileTimeToUnixTime(filetime);
     gmtime_r(&t1, result);
 }
 
 void pst_fileTimeToStructTM_bias(const FILETIME *filetime, struct tm *result, int32_t bias) {
     time_t t1;
     t1 = pst_fileTimeToUnixTime_bias(filetime, bias);
     gmtime_r(&t1, result);
 }
 
 time_t pst_fileTimeToUnixTime_bias(const FILETIME *filetime, int32_t tzBias)
 {
     uint64_t t = filetime->dwHighDateTime;
-    const uint64_t bias = 11644473600LL - (tzBias * 60);
+    const uint64_t bias = 11644473600LL + (tzBias * 60);
     t <<= 32;
     t += filetime->dwLowDateTime;
     t /= 10000000;
     t -= bias;
     return ((t > (uint64_t)0x000000007fffffff) && (sizeof(time_t) <= 4)) ? 0 : (time_t)t;
 }
 
 time_t pst_fileTimeToUnixTime(const FILETIME *filetime)
 {
     uint64_t t = filetime->dwHighDateTime;
     const uint64_t bias = 11644473600LL;
     t <<= 32;
     t += filetime->dwLowDateTime;
     t /= 10000000;
     t -= bias;
     return ((t > (uint64_t)0x000000007fffffff) && (sizeof(time_t) <= 4)) ? 0 : (time_t)t;
 }