diff --git a/sysutils.go b/sysutils.go
index 4b830ef..9978909 100644
--- a/sysutils.go
+++ b/sysutils.go
@@ -16,7 +16,7 @@ import (
 )
 
 func GetDaySeconds(seconds int64, timeZone int64) int64 {
-	return ((seconds+timeZone*3600)/3600/24+1)*3600*24 - 3600*timeZone
+	return ((seconds+timeZone*3600)/3600/24)*3600*24 - 3600*timeZone
 }
 
 func GetTickCount() int64 {