diff --git a/cli/tests/text_decoder_perf.js b/cli/tests/text_decoder_perf.js
new file mode 100644
index 0000000000..2e52b1f8be
--- /dev/null
+++ b/cli/tests/text_decoder_perf.js
@@ -0,0 +1,38 @@
+const mixed = new TextEncoder().encode("@Ā๐😀");
+
+function generateRandom(bytes) {
+  const result = new Uint8Array(bytes);
+  let i = 0;
+  while (i < bytes) {
+    const toAdd = Math.floor(Math.random() * Math.min(4, bytes - i));
+    switch (toAdd) {
+      case 0:
+        result[i] = mixed[0];
+        i++;
+        break;
+      case 1:
+        result[i] = mixed[1];
+        result[i + 1] = mixed[2];
+        i += 2;
+        break;
+      case 2:
+        result[i] = mixed[3];
+        result[i + 1] = mixed[4];
+        result[i + 2] = mixed[5];
+        i += 3;
+        break;
+      case 3:
+        result[i] = mixed[6];
+        result[i + 1] = mixed[7];
+        result[i + 2] = mixed[8];
+        result[i + 3] = mixed[9];
+        i += 4;
+        break;
+    }
+  }
+  return result;
+}
+
+const randomData = generateRandom(1024);
+const decoder = new TextDecoder();
+for (let i = 0; i < 10_000; i++) decoder.decode(randomData);
diff --git a/tools/benchmark.py b/tools/benchmark.py
index 85e126b880..6edeb1ee4d 100755
--- a/tools/benchmark.py
+++ b/tools/benchmark.py
@@ -27,6 +27,7 @@ exec_time_benchmarks = [
     ("cold_relative_import", ["--reload", "tests/003_relative_import.ts"]),
     ("workers_startup", ["tests/workers_startup_bench.ts"]),
     ("workers_round_robin", ["tests/workers_round_robin_bench.ts"]),
+    ("text_decoder", ["cli/tests/text_decoder_perf.js"]),
 ]
 
 
diff --git a/website/benchmarks.html b/website/benchmarks.html
index a8d4807807..80a47f03c6 100644
--- a/website/benchmarks.html
+++ b/website/benchmarks.html
@@ -185,6 +185,10 @@
           href="https://github.com/denoland/deno/blob/master/tests/003_relative_import.ts"
           >tests/003_relative_import.ts</a
         >,
+        <a
+          href="https://github.com/denoland/deno/blob/master/cli/tests/text_decoder_perf.js"
+          >cli/tests/text_decoder_perf.js</a
+        >,
         <a
           href="https://github.com/denoland/deno/blob/master/tests/workers_round_robin_bench.ts"
           >tests/workers_round_robin_bench.ts</a