diff --git a/benchmark.mjs b/benchmark.mjs
new file mode 100644
index 0000000..9a01ac4
--- /dev/null
+++ b/benchmark.mjs
@@ -0,0 +1,49 @@
+/* eslint no-undef: "off" */
+
+import {Buffer} from 'node:buffer';
+import {randomBytes} from 'node:crypto';
+import benchmark from 'benchmark';
+import {
+	base64ToString,
+	concatUint8Arrays,
+	hexToUint8Array,
+	isUint8Array,
+	stringToBase64,
+	stringToUint8Array,
+	uint8ArrayToBase64,
+	uint8ArrayToHex,
+	uint8ArrayToString,
+} from './index.js';
+
+const oneMb = 1024 * 1024;
+const largeUint8Array = new Uint8Array(randomBytes(oneMb).buffer);
+const textFromUint8Array = uint8ArrayToString(largeUint8Array);
+const base64FromUint8Array = Buffer.from(textFromUint8Array).toString('base64');
+const hexFromUint8Array = uint8ArrayToHex(largeUint8Array);
+
+const suite = new benchmark.Suite();
+
+suite.add('isUint8Array', () => isUint8Array(largeUint8Array));
+
+suite.add('concatUint8Arrays with 2 arrays', () => concatUint8Arrays([largeUint8Array, largeUint8Array]));
+
+suite.add('concatUint8Arrays with 3 arrays', () => concatUint8Arrays([largeUint8Array, largeUint8Array]));
+
+suite.add('concatUint8Arrays with 4 arrays', () => concatUint8Arrays([largeUint8Array, largeUint8Array, largeUint8Array, largeUint8Array]));
+
+suite.add('uint8ArrayToString', () => uint8ArrayToString(largeUint8Array));
+
+suite.add('stringToUint8Array', () => stringToUint8Array(textFromUint8Array));
+
+suite.add('uint8ArrayToBase64', () => uint8ArrayToBase64(largeUint8Array));
+
+suite.add('stringToBase64', () => stringToBase64(textFromUint8Array));
+
+suite.add('base64ToString', () => base64ToString(base64FromUint8Array));
+
+suite.add('uint8ArrayToHex', () => uint8ArrayToHex(largeUint8Array));
+
+suite.add('hexToUint8Array', () => hexToUint8Array(hexFromUint8Array));
+
+suite.on('cycle', event => console.log(event.target.toString()));
+suite.run({async: false});
diff --git a/index.js b/index.js
index bbe02f5..562945a 100644
--- a/index.js
+++ b/index.js
@@ -1,7 +1,16 @@
 const objectToString = Object.prototype.toString;
+const uint8ArrayStringified = '[object Uint8Array]';
 
 export function isUint8Array(value) {
-	return value && objectToString.call(value) === '[object Uint8Array]';
+	if (!value) {
+		return false;
+	}
+
+	if (value.constructor === Uint8Array) {
+		return true;
+	}
+
+	return objectToString.call(value) === uint8ArrayStringified;
 }
 
 export function assertUint8Array(value) {
@@ -92,9 +101,11 @@ export function compareUint8Arrays(a, b) {
 	return 0;
 }
 
+const cachedDecoder = new globalThis.TextDecoder();
+
 export function uint8ArrayToString(array) {
 	assertUint8Array(array);
-	return (new globalThis.TextDecoder()).decode(array);
+	return cachedDecoder.decode(array);
 }
 
 function assertString(value) {
@@ -103,9 +114,11 @@ function assertString(value) {
 	}
 }
 
+const cachedEncoder = new globalThis.TextEncoder();
+
 export function stringToUint8Array(string) {
 	assertString(string);
-	return (new globalThis.TextEncoder()).encode(string);
+	return cachedEncoder.encode(string);
 }
 
 function base64ToBase64Url(base64) {
@@ -116,11 +129,25 @@ function base64UrlToBase64(base64url) {
 	return base64url.replaceAll('-', '+').replaceAll('_', '/');
 }
 
+// Reference: https://phuoc.ng/collection/this-vs-that/concat-vs-push/
+const MAX_BLOCK_SIZE = 65_535;
+
 export function uint8ArrayToBase64(array, {urlSafe = false} = {}) {
 	assertUint8Array(array);
 
+	let base64;
+
+	if (array.length < MAX_BLOCK_SIZE) {
 	// Required as `btoa` and `atob` don't properly support Unicode: https://developer.mozilla.org/en-US/docs/Glossary/Base64#the_unicode_problem
-	const base64 = globalThis.btoa(String.fromCodePoint(...array));
+		base64 = globalThis.btoa(String.fromCodePoint.apply(this, array));
+	} else {
+		base64 = '';
+		for (const value of array) {
+			base64 += String.fromCodePoint(value);
+		}
+
+		base64 = globalThis.btoa(base64);
+	}
 
 	return urlSafe ? base64ToBase64Url(base64) : base64;
 }
diff --git a/package.json b/package.json
index dcef9ec..58c945d 100644
--- a/package.json
+++ b/package.json
@@ -48,6 +48,7 @@
 	"devDependencies": {
 		"ava": "^5.3.1",
 		"typescript": "^5.2.2",
-		"xo": "^0.56.0"
+		"xo": "^0.56.0",
+		"benchmark": "2.1.4"
 	}
 }
diff --git a/test.js b/test.js
index 92fd192..afa914a 100644
--- a/test.js
+++ b/test.js
@@ -126,6 +126,12 @@ test('uint8ArrayToBase64 and base64ToUint8Array', t => {
 	t.deepEqual(base64ToUint8Array(base64), fixture);
 });
 
+test('should handle uint8ArrayToBase64 with 200k items', t => {
+	const fixture = stringToUint8Array('H'.repeat(200_000));
+	const base64 = uint8ArrayToBase64(fixture);
+	t.deepEqual(base64ToUint8Array(base64), fixture);
+});
+
 test('uint8ArrayToBase64 and base64ToUint8Array #2', t => {
 	const fixture = stringToUint8Array('a Ā 𐀀 文 🦄');
 	t.deepEqual(base64ToUint8Array(uint8ArrayToBase64(base64ToUint8Array(uint8ArrayToBase64(fixture)))), fixture);