diff --git a/util.go b/util.go
index 05aecc6..1c03dfb 100644
--- a/util.go
+++ b/util.go
@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"reflect"
+	"strconv"
 )
 
 // format bytes number friendly
@@ -75,3 +76,16 @@ func CopyStruct(dst interface{}, src interface{}) {
 	}
 
 }
+
+func FormatBytes(bytes int64) string {
+	const unit = 1024
+	if bytes < unit {
+		return strconv.FormatInt(bytes, 10) + " B"
+	}
+	div, exp := int64(unit), 0
+	for n := bytes / unit; n >= unit; n /= unit {
+		div *= unit
+		exp++
+	}
+	return fmt.Sprintf("%.2f%cB", float64(bytes)/float64(div), "KMGTPE"[exp])
+}