diff --git a/benchmark/buffers/buffer-base64-decode.js b/benchmark/buffers/buffer-base64-decode.js
index 4a8ed4466df413..f98e621c2dd836 100644
--- a/benchmark/buffers/buffer-base64-decode.js
+++ b/benchmark/buffers/buffer-base64-decode.js
@@ -15,7 +15,15 @@ function main({ n, size }) {
   assert.strictEqual(s.length % 4, 0);
   const b = Buffer.allocUnsafe(encodedSize);
   b.write(s, 0, encodedSize, 'base64');
+
+  let tmp;
+
   bench.start();
-  for (let i = 0; i < n; i += 1) b.base64Write(s, 0, s.length);
+
+  for (let i = 0; i < n; i += 1)
+    tmp = b.base64Write(s, 0, s.length);
+
   bench.end(n);
+
+  assert.strictEqual(tmp, encodedSize);
 }
diff --git a/benchmark/buffers/buffer-base64-encode.js b/benchmark/buffers/buffer-base64-encode.js
index 0571f3181ae4e2..99f633b65fd871 100644
--- a/benchmark/buffers/buffer-base64-encode.js
+++ b/benchmark/buffers/buffer-base64-encode.js
@@ -21,6 +21,7 @@
 
 'use strict';
 const common = require('../common.js');
+const assert = require('assert');
 
 const bench = common.createBenchmark(main, {
   len: [64 * 1024 * 1024],
@@ -35,7 +36,15 @@ function main({ n, len }) {
   let i;
   for (i = 0; i < 256; ++i) s += String.fromCharCode(i);
   for (i = 0; i < len; i += 256) b.write(s, i, 256, 'ascii');
+
+  let tmp;
+
   bench.start();
-  for (i = 0; i < n; ++i) b.toString('base64');
+
+  for (i = 0; i < n; ++i)
+    tmp = b.toString('base64');
+
   bench.end(n);
+
+  assert.strictEqual(typeof tmp, 'string');
 }
diff --git a/benchmark/buffers/buffer-base64url-decode.js b/benchmark/buffers/buffer-base64url-decode.js
new file mode 100644
index 00000000000000..276dfc8d23b543
--- /dev/null
+++ b/benchmark/buffers/buffer-base64url-decode.js
@@ -0,0 +1,29 @@
+'use strict';
+const assert = require('assert');
+const common = require('../common.js');
+
+const bench = common.createBenchmark(main, {
+  n: [32],
+  size: [8 << 20],
+});
+
+function main({ n, size }) {
+  const s = 'abcd'.repeat(size);
+  const encodedSize = s.length * 3 / 4;
+  // eslint-disable-next-line node-core/no-unescaped-regexp-dot
+  s.match(/./);  // Flatten string.
+  assert.strictEqual(s.length % 4, 0);
+  const b = Buffer.allocUnsafe(encodedSize);
+  b.write(s, 0, encodedSize, 'base64url');
+
+  let tmp;
+
+  bench.start();
+
+  for (let i = 0; i < n; i += 1)
+    tmp = b.base64Write(s, 0, s.length);
+
+  bench.end(n);
+
+  assert.strictEqual(tmp, encodedSize);
+}
diff --git a/benchmark/buffers/buffer-base64url-encode.js b/benchmark/buffers/buffer-base64url-encode.js
new file mode 100644
index 00000000000000..cb4ea28c29d005
--- /dev/null
+++ b/benchmark/buffers/buffer-base64url-encode.js
@@ -0,0 +1,29 @@
+'use strict';
+const common = require('../common.js');
+const assert = require('assert');
+
+const bench = common.createBenchmark(main, {
+  len: [64 * 1024 * 1024],
+  n: [32],
+}, {
+  test: { len: 256 },
+});
+
+function main({ n, len }) {
+  const b = Buffer.allocUnsafe(len);
+  let s = '';
+  let i;
+  for (i = 0; i < 256; ++i) s += String.fromCharCode(i);
+  for (i = 0; i < len; i += 256) b.write(s, i, 256, 'ascii');
+
+  let tmp;
+
+  bench.start();
+
+  for (i = 0; i < n; ++i)
+    tmp = b.toString('base64url');
+
+  bench.end(n);
+
+  assert.strictEqual(typeof tmp, 'string');
+}
diff --git a/benchmark/buffers/buffer-hex-decode.js b/benchmark/buffers/buffer-hex-decode.js
new file mode 100644
index 00000000000000..4d4db07238c630
--- /dev/null
+++ b/benchmark/buffers/buffer-hex-decode.js
@@ -0,0 +1,29 @@
+'use strict';
+
+const common = require('../common.js');
+const assert = require('assert');
+
+const bench = common.createBenchmark(main, {
+  len: [64, 1024],
+  n: [1e6],
+});
+
+function main({ len, n }) {
+  const buf = Buffer.alloc(len);
+
+  for (let i = 0; i < buf.length; i++)
+    buf[i] = i & 0xff;
+
+  const plain = buf;
+
+  bench.start();
+
+  let tmp;
+
+  for (let i = 0; i < n; i += 1)
+    tmp = plain.toString('hex');
+
+  bench.end(n);
+
+  assert.strictEqual(typeof tmp, 'string');
+}
diff --git a/benchmark/buffers/buffer-hex.js b/benchmark/buffers/buffer-hex-encode.js
similarity index 74%
rename from benchmark/buffers/buffer-hex.js
rename to benchmark/buffers/buffer-hex-encode.js
index 6e61d71c9bacf1..d038ce95f0aec8 100644
--- a/benchmark/buffers/buffer-hex.js
+++ b/benchmark/buffers/buffer-hex-encode.js
@@ -1,6 +1,7 @@
 'use strict';
 
 const common = require('../common.js');
+const assert = require('assert');
 
 const bench = common.createBenchmark(main, {
   len: [64, 1024],
@@ -14,11 +15,14 @@ function main({ len, n }) {
     buf[i] = i & 0xff;
 
   const hex = buf.toString('hex');
+  let tmp;
 
   bench.start();
 
   for (let i = 0; i < n; i += 1)
-    Buffer.from(hex, 'hex');
+    tmp = Buffer.from(hex, 'hex');
 
   bench.end(n);
+
+  assert.strictEqual(typeof tmp, 'object');
 }