diff --git a/internal/merch/helper.go b/internal/merch/helper.go
index 027feb1..95fdec2 100644
--- a/internal/merch/helper.go
+++ b/internal/merch/helper.go
@@ -3,6 +3,7 @@ package merch
 import (
 	"github.com/gin-gonic/gin"
 	log "github.com/sirupsen/logrus"
+	"time"
 )
 
 const (
@@ -23,3 +24,10 @@ func getUserId(c *gin.Context) int64 {
 	id, _ := c.Get("userId")
 	return id.(int64)
 }
+
+func getPeriod(days int) time.Time {
+	if days > 365 {
+		days = 7
+	}
+	return time.Now().UTC().Add(-(time.Duration(days) * time.Hour * 24))
+}