Cryptography & Security

TOTP Code Generator

Paste a Base32 authenticator secret to see the current one-time code and a live countdown to the next refresh.

Free & unlimitedRuns in your browserNo sign-up required

Base32 Secret Key

Current Code

000 000

Updates in 0s

TOTP Code Generator

The six-digit code your authenticator app shows you every 30 seconds is called a TOTP: Time-based One-Time Password. It's one of the most widely deployed pieces of applied cryptography most people interact with daily without knowing its name.

How TOTP works

TOTP works by combining a shared secret, established once when you first set up 2FA and stored as a Base32-encoded string, with the current time, rounded to a fixed interval, usually 30 seconds. Both your device and the server run the same calculation independently. Since they share the same secret and (roughly) the same clock, they arrive at the same six-digit code without ever having to communicate during the actual login. That's why 2FA still works even when your phone is in airplane mode.

Debugging clock drift

If your application's TOTP verification keeps rejecting valid-looking codes, the most common cause by far is clock drift between your server and the actual time standard. TOTP typically allows a small window of tolerance (usually one interval before or after) to account for minor drift, but if your server's clock is more than that off, every code will fail even though the secret and algorithm are both correct.

Testing and validation

This tool generates live TOTP codes from a Base32 secret, fully compatible with the same algorithm Google Authenticator and Authy use, which means you can test your own 2FA setup, debug an authentication integration you're building, or verify a code without needing your phone in hand.

Important safety note

Never paste a real Base32 secret from an account you actually use for security into any third-party tool, including this one, since anyone with your secret can generate valid codes indefinitely. Use this for testing accounts, learning how TOTP works, or debugging your own application's implementation.

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How it works

Three steps, no setup

Paste the secret

This is the Base32 string shown when an app sets up two-factor authentication.

Watch the live code

A new 6-digit code is calculated every 30 seconds, matching your authenticator app.

Use it for testing

Handy for automated test suites that need to log in behind 2FA.

Common questions

Frequently asked questions

Is this the same algorithm as my phone app?

Yes — it implements the standard TOTP algorithm (RFC 6238), the same one used by Google Authenticator, Authy, and most 2FA apps.

Why did the code not match?

TOTP codes depend on accurate clocks. If your computer's system time has drifted, the generated code will not line up with your phone.

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