diff --git a/gototp.go b/gototp.go
index 1d770c2..d07ea48 100644
--- a/gototp.go
+++ b/gototp.go
@@ -56,7 +56,7 @@ func (totp *TOTP) Now() int32 {
 // will be valid in the next period (FromNow(1)).
 // This means that every code is therefore valid for 3 * totp.Period.
 func (totp *TOTP) FromNow(periods int64) int32 {
-	period := (time.Now().Unix() / int64(totp.Period)) + int64(periods)
+	period := math.Floor(time.Now().Unix() / int64(totp.Period)) + int64(periods)
 	return totp.ForPeriod(period)
 }