diff --git a/x-pack/plugins/monitoring/public/lib/format_number.test.js b/x-pack/plugins/monitoring/public/lib/format_number.test.js
index 551ec1e6a4096..b93f9101a4df2 100644
--- a/x-pack/plugins/monitoring/public/lib/format_number.test.js
+++ b/x-pack/plugins/monitoring/public/lib/format_number.test.js
@@ -32,7 +32,7 @@ describe('format_number', () => {
     });
 
     it('should format time in H:mm:ss', () => {
-      expect(formatNumber(1461868937000, 'time')).to.match(/\d\d:\d\d:\d\d/);
+      expect(formatNumber(1461868937000, 'time')).to.match(/[12]?\d:\d\d:\d\d/);
     });
 
     it('should format integers with commas', () => {