Generate random letters and numbers together, also called a random alphanumeric string. Pick the length and how many you need, choose uppercase, lowercase or mixed, then copy or download the list.
What is a random alphanumeric string?
An alphanumeric string mixes letters (A–Z, a–z) and digits (0–9), like K7QX2M9A. With uppercase letters and digits there are 36 possible characters per position, so an 8-character code has more than 2.8 trillion combinations. That's why the format is used for codes that must be short but hard to guess.
Common uses
- Codes and IDs: voucher codes, order references, ticket numbers, and invite codes. Tick "No duplicate results" so every code is unique.
- Test data: placeholder usernames, product SKUs, and IDs for software testing.
- Classroom and games: seat and locker codes, bingo-style calls, or grid coordinates like "C4".
- Passwords and PINs: generate a long mixed-case string. It's created in your browser and never sent anywhere.
Fixed patterns: letters first, then numbers
If you need a fixed shape like two letters then two digits ("KD-07"), use the Letters + Numbers tab on the main random letter generator. You set the letter count and digit count separately, and team mode can give each team its own code.
How many combinations are possible?
| Characters | A–Z + 0–9 (36) | A–Z + a–z + 0–9 (62) |
|---|---|---|
| 4 | 1.7 million | 14.8 million |
| 6 | 2.2 billion | 56.8 billion |
| 8 | 2.8 trillion | 218 trillion |
| 12 | 4.7 × 1018 | 3.2 × 1021 |
Generating them in code
Want the same thing in your own program? See our Java random string guide or the Python random letter guide.
Frequently asked questions
How do I generate random letters and numbers together?
Leave "Include numbers 0–9" ticked, set how many characters each result should have and how many results you want, then press Generate. Each result mixes letters A–Z and digits 0–9 at random.
Can I make a random code like AB12 or K7Q9?
Yes. Set characters per result to 4 and press Generate. To force a fixed pattern like two letters then two numbers, use the Letters + Numbers tab on the main random letter generator, which builds results like "AB-12".
Can I avoid confusing characters like 0 and O?
Yes. Tick "Skip look-alikes" to remove 0, O, 1, I and l, so codes are easy to read aloud or type.
Can I generate only numbers?
Yes. Set Letters to "No letters (numbers only)" and keep numbers ticked to get random digit strings.
Is this generator safe for passwords?
It uses your browser's cryptographically secure random number generator (crypto.getRandomValues), and nothing is sent to a server. For real passwords, use at least 16 characters with mixed case and numbers.
Does it include special characters?
Not by default. Choose "Custom set" and type the exact letters, digits and symbols you want, for example ABC123!@#.