diff --git a/benchmark/url/legacy-vs-whatwg-url-parse.js b/benchmark/url/legacy-vs-whatwg-url-parse.js
index 6e5e25d231242f..94115d1305bb95 100644
--- a/benchmark/url/legacy-vs-whatwg-url-parse.js
+++ b/benchmark/url/legacy-vs-whatwg-url-parse.js
@@ -13,7 +13,7 @@ const bench = common.createBenchmark(main, {
 
 function useLegacy(data) {
   const len = data.length;
-  var result = url.parse(data[0]);  // Avoid dead code elimination
+  let result = url.parse(data[0]);  // Avoid dead code elimination
   bench.start();
   for (let i = 0; i < len; ++i) {
     result = url.parse(data[i]);
@@ -24,7 +24,7 @@ function useLegacy(data) {
 
 function useWHATWGWithBase(data) {
   const len = data.length;
-  var result = new URL(data[0][0], data[0][1]);  // Avoid dead code elimination
+  let result = new URL(data[0][0], data[0][1]);  // Avoid dead code elimination
   bench.start();
   for (let i = 0; i < len; ++i) {
     const item = data[i];
@@ -36,7 +36,7 @@ function useWHATWGWithBase(data) {
 
 function useWHATWGWithoutBase(data) {
   const len = data.length;
-  var result = new URL(data[0]);  // Avoid dead code elimination
+  let result = new URL(data[0]);  // Avoid dead code elimination
   bench.start();
   for (let i = 0; i < len; ++i) {
     result = new URL(data[i]);
@@ -47,8 +47,8 @@ function useWHATWGWithoutBase(data) {
 
 function main({ e, method, type, withBase }) {
   withBase = withBase === 'true';
-  var noDead;  // Avoid dead code elimination.
-  var data;
+  let noDead;  // Avoid dead code elimination.
+  let data;
   switch (method) {
     case 'legacy':
       data = common.bakeUrlData(type, e, false, false);
diff --git a/benchmark/url/legacy-vs-whatwg-url-serialize.js b/benchmark/url/legacy-vs-whatwg-url-serialize.js
index 5523e549ceb233..e3254ede3acee8 100644
--- a/benchmark/url/legacy-vs-whatwg-url-serialize.js
+++ b/benchmark/url/legacy-vs-whatwg-url-serialize.js
@@ -13,7 +13,7 @@ const bench = common.createBenchmark(main, {
 function useLegacy(data) {
   const obj = url.parse(data[0]);
   const len = data.length;
-  var noDead = url.format(obj);
+  let noDead = url.format(obj);
   bench.start();
   for (let i = 0; i < len; i++) {
     noDead = data[i].toString();
@@ -25,7 +25,7 @@ function useLegacy(data) {
 function useWHATWG(data) {
   const obj = new URL(data[0]);
   const len = data.length;
-  var noDead = obj.toString();
+  let noDead = obj.toString();
   bench.start();
   for (let i = 0; i < len; i++) {
     noDead = data[i].toString();
@@ -37,7 +37,7 @@ function useWHATWG(data) {
 function main({ type, e, method }) {
   const data = common.bakeUrlData(type, e, false, false);
 
-  var noDead;  // Avoid dead code elimination.
+  let noDead;  // Avoid dead code elimination.
   switch (method) {
     case 'legacy':
       noDead = useLegacy(data);
diff --git a/benchmark/url/whatwg-url-properties.js b/benchmark/url/whatwg-url-properties.js
index ac71ff4f636d66..f0ba2931e51f1e 100644
--- a/benchmark/url/whatwg-url-properties.js
+++ b/benchmark/url/whatwg-url-properties.js
@@ -12,7 +12,7 @@ const bench = common.createBenchmark(main, {
 
 function setAndGet(data, prop) {
   const len = data.length;
-  var result = data[0][prop];
+  let result = data[0][prop];
   bench.start();
   for (let i = 0; i < len; ++i) {
     result = data[i][prop];
@@ -24,7 +24,7 @@ function setAndGet(data, prop) {
 
 function get(data, prop) {
   const len = data.length;
-  var result = data[0][prop];
+  let result = data[0][prop];
   bench.start();
   for (let i = 0; i < len; ++i) {
     result = data[i][prop]; // get