diff --git a/src/stringify-internal.js b/src/stringify-internal.js
new file mode 100644
index 00000000..c479931d
--- /dev/null
+++ b/src/stringify-internal.js
@@ -0,0 +1,312 @@
+/**
+ * This is the internal `stringify()` function used by the library.
+ * It isn't exposed in the index because it assumes no offset.
+ */
+
+import validate from './validate.js';
+
+/**
+ * Convert array of 16 byte values to UUID string format of the form:
+ * XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX
+ */
+const byteToHex = [
+  '00',
+  '01',
+  '02',
+  '03',
+  '04',
+  '05',
+  '06',
+  '07',
+  '08',
+  '09',
+  '0a',
+  '0b',
+  '0c',
+  '0d',
+  '0e',
+  '0f',
+  '10',
+  '11',
+  '12',
+  '13',
+  '14',
+  '15',
+  '16',
+  '17',
+  '18',
+  '19',
+  '1a',
+  '1b',
+  '1c',
+  '1d',
+  '1e',
+  '1f',
+  '20',
+  '21',
+  '22',
+  '23',
+  '24',
+  '25',
+  '26',
+  '27',
+  '28',
+  '29',
+  '2a',
+  '2b',
+  '2c',
+  '2d',
+  '2e',
+  '2f',
+  '30',
+  '31',
+  '32',
+  '33',
+  '34',
+  '35',
+  '36',
+  '37',
+  '38',
+  '39',
+  '3a',
+  '3b',
+  '3c',
+  '3d',
+  '3e',
+  '3f',
+  '40',
+  '41',
+  '42',
+  '43',
+  '44',
+  '45',
+  '46',
+  '47',
+  '48',
+  '49',
+  '4a',
+  '4b',
+  '4c',
+  '4d',
+  '4e',
+  '4f',
+  '50',
+  '51',
+  '52',
+  '53',
+  '54',
+  '55',
+  '56',
+  '57',
+  '58',
+  '59',
+  '5a',
+  '5b',
+  '5c',
+  '5d',
+  '5e',
+  '5f',
+  '60',
+  '61',
+  '62',
+  '63',
+  '64',
+  '65',
+  '66',
+  '67',
+  '68',
+  '69',
+  '6a',
+  '6b',
+  '6c',
+  '6d',
+  '6e',
+  '6f',
+  '70',
+  '71',
+  '72',
+  '73',
+  '74',
+  '75',
+  '76',
+  '77',
+  '78',
+  '79',
+  '7a',
+  '7b',
+  '7c',
+  '7d',
+  '7e',
+  '7f',
+  '80',
+  '81',
+  '82',
+  '83',
+  '84',
+  '85',
+  '86',
+  '87',
+  '88',
+  '89',
+  '8a',
+  '8b',
+  '8c',
+  '8d',
+  '8e',
+  '8f',
+  '90',
+  '91',
+  '92',
+  '93',
+  '94',
+  '95',
+  '96',
+  '97',
+  '98',
+  '99',
+  '9a',
+  '9b',
+  '9c',
+  '9d',
+  '9e',
+  '9f',
+  'a0',
+  'a1',
+  'a2',
+  'a3',
+  'a4',
+  'a5',
+  'a6',
+  'a7',
+  'a8',
+  'a9',
+  'aa',
+  'ab',
+  'ac',
+  'ad',
+  'ae',
+  'af',
+  'b0',
+  'b1',
+  'b2',
+  'b3',
+  'b4',
+  'b5',
+  'b6',
+  'b7',
+  'b8',
+  'b9',
+  'ba',
+  'bb',
+  'bc',
+  'bd',
+  'be',
+  'bf',
+  'c0',
+  'c1',
+  'c2',
+  'c3',
+  'c4',
+  'c5',
+  'c6',
+  'c7',
+  'c8',
+  'c9',
+  'ca',
+  'cb',
+  'cc',
+  'cd',
+  'ce',
+  'cf',
+  'd0',
+  'd1',
+  'd2',
+  'd3',
+  'd4',
+  'd5',
+  'd6',
+  'd7',
+  'd8',
+  'd9',
+  'da',
+  'db',
+  'dc',
+  'dd',
+  'de',
+  'df',
+  'e0',
+  'e1',
+  'e2',
+  'e3',
+  'e4',
+  'e5',
+  'e6',
+  'e7',
+  'e8',
+  'e9',
+  'ea',
+  'eb',
+  'ec',
+  'ed',
+  'ee',
+  'ef',
+  'f0',
+  'f1',
+  'f2',
+  'f3',
+  'f4',
+  'f5',
+  'f6',
+  'f7',
+  'f8',
+  'f9',
+  'fa',
+  'fb',
+  'fc',
+  'fd',
+  'fe',
+  'ff',
+];
+
+export function unsafeStringify(arr) {
+  // Note: Be careful editing this code!  It's been tuned for performance
+  // and works in ways you may not expect. See https://github.com/uuidjs/uuid/pull/434
+  return (
+    byteToHex[arr[0]] +
+    byteToHex[arr[1]] +
+    byteToHex[arr[2]] +
+    byteToHex[arr[3]] +
+    '-' +
+    byteToHex[arr[4]] +
+    byteToHex[arr[5]] +
+    '-' +
+    byteToHex[arr[6]] +
+    byteToHex[arr[7]] +
+    '-' +
+    byteToHex[arr[8]] +
+    byteToHex[arr[9]] +
+    '-' +
+    byteToHex[arr[10]] +
+    byteToHex[arr[11]] +
+    byteToHex[arr[12]] +
+    byteToHex[arr[13]] +
+    byteToHex[arr[14]] +
+    byteToHex[arr[15]]
+  ).toLowerCase();
+}
+
+function stringify(arr) {
+  const uuid = unsafeStringify(arr);
+  // Consistency check for valid UUID.  If this throws, it's likely due to one
+  // of the following:
+  // - One or more input array values don't map to a hex octet (leading to
+  // "undefined" in the uuid)
+  // - Invalid input values for the RFC `version` or `variant` fields
+  if (!validate(uuid)) {
+    throw TypeError('Stringified UUID is invalid');
+  }
+
+  return uuid;
+}
+
+export default stringify;
diff --git a/src/stringify.js b/src/stringify.js
index 3e66728d..49401e12 100644
--- a/src/stringify.js
+++ b/src/stringify.js
@@ -4,11 +4,264 @@ import validate from './validate.js';
  * Convert array of 16 byte values to UUID string format of the form:
  * XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX
  */
-const byteToHex = [];
-
-for (let i = 0; i < 256; ++i) {
-  byteToHex.push((i + 0x100).toString(16).slice(1));
-}
+const byteToHex = [
+  '00',
+  '01',
+  '02',
+  '03',
+  '04',
+  '05',
+  '06',
+  '07',
+  '08',
+  '09',
+  '0a',
+  '0b',
+  '0c',
+  '0d',
+  '0e',
+  '0f',
+  '10',
+  '11',
+  '12',
+  '13',
+  '14',
+  '15',
+  '16',
+  '17',
+  '18',
+  '19',
+  '1a',
+  '1b',
+  '1c',
+  '1d',
+  '1e',
+  '1f',
+  '20',
+  '21',
+  '22',
+  '23',
+  '24',
+  '25',
+  '26',
+  '27',
+  '28',
+  '29',
+  '2a',
+  '2b',
+  '2c',
+  '2d',
+  '2e',
+  '2f',
+  '30',
+  '31',
+  '32',
+  '33',
+  '34',
+  '35',
+  '36',
+  '37',
+  '38',
+  '39',
+  '3a',
+  '3b',
+  '3c',
+  '3d',
+  '3e',
+  '3f',
+  '40',
+  '41',
+  '42',
+  '43',
+  '44',
+  '45',
+  '46',
+  '47',
+  '48',
+  '49',
+  '4a',
+  '4b',
+  '4c',
+  '4d',
+  '4e',
+  '4f',
+  '50',
+  '51',
+  '52',
+  '53',
+  '54',
+  '55',
+  '56',
+  '57',
+  '58',
+  '59',
+  '5a',
+  '5b',
+  '5c',
+  '5d',
+  '5e',
+  '5f',
+  '60',
+  '61',
+  '62',
+  '63',
+  '64',
+  '65',
+  '66',
+  '67',
+  '68',
+  '69',
+  '6a',
+  '6b',
+  '6c',
+  '6d',
+  '6e',
+  '6f',
+  '70',
+  '71',
+  '72',
+  '73',
+  '74',
+  '75',
+  '76',
+  '77',
+  '78',
+  '79',
+  '7a',
+  '7b',
+  '7c',
+  '7d',
+  '7e',
+  '7f',
+  '80',
+  '81',
+  '82',
+  '83',
+  '84',
+  '85',
+  '86',
+  '87',
+  '88',
+  '89',
+  '8a',
+  '8b',
+  '8c',
+  '8d',
+  '8e',
+  '8f',
+  '90',
+  '91',
+  '92',
+  '93',
+  '94',
+  '95',
+  '96',
+  '97',
+  '98',
+  '99',
+  '9a',
+  '9b',
+  '9c',
+  '9d',
+  '9e',
+  '9f',
+  'a0',
+  'a1',
+  'a2',
+  'a3',
+  'a4',
+  'a5',
+  'a6',
+  'a7',
+  'a8',
+  'a9',
+  'aa',
+  'ab',
+  'ac',
+  'ad',
+  'ae',
+  'af',
+  'b0',
+  'b1',
+  'b2',
+  'b3',
+  'b4',
+  'b5',
+  'b6',
+  'b7',
+  'b8',
+  'b9',
+  'ba',
+  'bb',
+  'bc',
+  'bd',
+  'be',
+  'bf',
+  'c0',
+  'c1',
+  'c2',
+  'c3',
+  'c4',
+  'c5',
+  'c6',
+  'c7',
+  'c8',
+  'c9',
+  'ca',
+  'cb',
+  'cc',
+  'cd',
+  'ce',
+  'cf',
+  'd0',
+  'd1',
+  'd2',
+  'd3',
+  'd4',
+  'd5',
+  'd6',
+  'd7',
+  'd8',
+  'd9',
+  'da',
+  'db',
+  'dc',
+  'dd',
+  'de',
+  'df',
+  'e0',
+  'e1',
+  'e2',
+  'e3',
+  'e4',
+  'e5',
+  'e6',
+  'e7',
+  'e8',
+  'e9',
+  'ea',
+  'eb',
+  'ec',
+  'ed',
+  'ee',
+  'ef',
+  'f0',
+  'f1',
+  'f2',
+  'f3',
+  'f4',
+  'f5',
+  'f6',
+  'f7',
+  'f8',
+  'f9',
+  'fa',
+  'fb',
+  'fc',
+  'fd',
+  'fe',
+  'ff',
+];
 
 export function unsafeStringify(arr, offset = 0) {
   // Note: Be careful editing this code!  It's been tuned for performance
diff --git a/src/v1.js b/src/v1.js
index 85b7a7a8..044eb761 100644
--- a/src/v1.js
+++ b/src/v1.js
@@ -1,5 +1,5 @@
 import rng from './rng.js';
-import { unsafeStringify } from './stringify.js';
+import { unsafeStringify } from './stringify-internal.js';
 
 // **`v1()` - Generate time-based UUID**
 //
diff --git a/src/v35.js b/src/v35.js
index 1e56eea5..a3cc61dc 100644
--- a/src/v35.js
+++ b/src/v35.js
@@ -1,4 +1,4 @@
-import { unsafeStringify } from './stringify.js';
+import { unsafeStringify } from './stringify-internal.js';
 import parse from './parse.js';
 
 function stringToBytes(str) {
diff --git a/src/v4.js b/src/v4.js
index dc21c59f..5200d00b 100644
--- a/src/v4.js
+++ b/src/v4.js
@@ -1,6 +1,6 @@
 import native from './native.js';
 import rng from './rng.js';
-import { unsafeStringify } from './stringify.js';
+import { unsafeStringify } from './stringify-internal.js';
 
 function v4(options, buf, offset) {
   if (native.randomUUID && !buf && !options) {