diff --git a/web/pages/components/chart.tsx b/web/pages/components/chart.tsx
index f7d1a6d83..e1680bf78 100644
--- a/web/pages/components/chart.tsx
+++ b/web/pages/components/chart.tsx
@@ -4,6 +4,7 @@ import { timeFormat } from "d3-time-format";
 interface ToolTipProps {
   active?: boolean,
   payload?: object,
+  unit?: string
 };
 const defaultProps = {
   active: false,