How do I get my 2FA code when I lost my Authenticator phone?
Paste a TOTP secret (base32 or otpauth:// URI) and the tool shows the current 6-digit code live with a countdown to the next rotation.
Same thing Google Authenticator does on your phone, just in the browser. The secret never reaches a server.
Useful when: you lost the phone with 2FA and need access, you want a backup generator on a desktop, you're debugging a 2FA integration in your own app.
How to use it
- Paste a base32 secret (e.g. "JBSWY3DPEHPK3PXP") or a full otpauth:// URI, the tool detects URIs and fills every field.
- Defaults: SHA-1 + 6 digits + 30s, what Google Authenticator, Authy, 1Password use. Change only if your service requires otherwise.
- The current code appears immediately with a countdown bar to the next rotation.
- Click the code = copy to clipboard.
- After 30 seconds the code rotates automatically, just like Authenticator on your phone.
When this is useful
Five typical situations where a TOTP calculator replaces the phone app:
- Recovery. You lost / broke the phone with 2FA, but saved the secret (usually with backup codes at enrollment); paste here, get the code, sign in.
- Debugging. You're writing a 2FA integration and want to verify your backend returns the same codes as Google Authenticator.
- Backup. TOTP secret cross-platform sync still isn't great; keep this calculator bookmarked as a "secondary device".
- Education. See how 2FA actually works: HMAC-SHA-1 + Unix time + dynamic truncation = 6-digit code.
- Security audit. Test whether an app accepts weak secrets or is vulnerable to replay attacks.
To generate a fresh secret, use the TOTP secret generator.
Questions and answers
No. All compute is local: we decode the base32 secret to bytes, run HMAC-SHA-1 with Unix time via Web Crypto API, modulo the result. You can verify in DevTools (Network), no upload.