diff --git a/benchmark/common.js b/benchmark/common.js
index 622d053e5f9..148f51830f7 100644
--- a/benchmark/common.js
+++ b/benchmark/common.js
@@ -217,7 +217,7 @@ function formatResult(data) {
   }
 
   var rate = data.rate.toString().split('.');
-  rate[0] = rate[0].replace(/(\d)(?=(\d\d\d)+(?!\d))/g, '$1,');
+  rate[0] = rate[0].replace(/(\d)(?=(?:\d\d\d)+(?!\d))/g, '$1,');
   rate = (rate[1] ? rate.join('.') : rate[0]);
   return `${data.name}${conf}: ${rate}`;
 }
diff --git a/benchmark/run.js b/benchmark/run.js
index 3b4944caf5c..2b263a1a6cb 100644
--- a/benchmark/run.js
+++ b/benchmark/run.js
@@ -60,7 +60,7 @@ if (format === 'csv') {
       console.log(`"${data.name}", "${conf}", ${data.rate}, ${data.time}`);
     } else {
       var rate = data.rate.toString().split('.');
-      rate[0] = rate[0].replace(/(\d)(?=(\d\d\d)+(?!\d))/g, '$1,');
+      rate[0] = rate[0].replace(/(\d)(?=(?:\d\d\d)+(?!\d))/g, '$1,');
       rate = (rate[1] ? rate.join('.') : rate[0]);
       console.log(`${data.name} ${conf}: ${rate}`);
     }