TOTP Generator

TOTP (Time-based One-Time Password) uses a shared secret and the current time to generate a code that changes every 30 seconds. The algorithm takes the secret key, combines it with a time counter (current Unix time divided by the period), and runs it through HMAC-SHA1 to produce a 6 or 8-digit code.

This is the same algorithm behind Google Authenticator, Authy, 1Password, and Microsoft Authenticator. The secret key is typically shared as a Base32-encoded string or QR code during 2FA setup. Both the server and your authenticator app independently generate the same code from the same secret and time — no network request needed.

This tool is useful for developers testing 2FA integrations, verifying that a secret key produces the expected codes, or debugging authentication flows. Enter any Base32 secret to see live rotating codes. Everything runs in your browser using the Web Crypto API — your secret never leaves your device.