How does the 6-digit code get calculated?

The secret plus the current time (in 30-second steps) go through HMAC, and a slice of the result becomes the code. Same secret + same time window = same code, which is why phone and server agree.

Why did my code stop matching?

Clock drift. TOTP depends on the device clock — too large a difference from the server makes codes fail indefinitely. Re-sync the device time or re-enrol the secret.

Is the base32 secret sensitive?

Completely — anyone holding it can generate your codes forever. Store it like a password, and enrol it in an authenticator app rather than pasting it around.

OTP code generator — Guide

Generate and validate time-based OTP (one time password) for multi-factor authentication.

What it is and when to use it

Generate and validate time-based one-time passwords (TOTP) from a base32 secret — the same mechanism behind Google Authenticator-style codes. Useful for testing your own MFA implementation, decoding a setup key before scanning it into an app, or verifying that a code is currently valid.

Generates and verifies time-based one-time passwords (TOTP) for two-factor authentication setups.

How to use it

Enter the secret (Base32)
Click generate to get the current code
To verify, enter the code the other party provided and compare

A worked example

Paste a sample Base32 secret

JBSWY3DPEHPK3PXP

Copy this into the tool, or open OTP code generator

Things that trip people up

TOTP depends on the device clock — too large a time difference makes codes fail to match indefinitely

Questions people ask

How does the 6-digit code get calculated?: The secret plus the current time (in 30-second steps) go through HMAC, and a slice of the result becomes the code. Same secret + same time window = same code, which is why phone and server agree.
Why did my code stop matching?: Clock drift. TOTP depends on the device clock — too large a difference from the server makes codes fail indefinitely. Re-sync the device time or re-enrol the secret.
Is the base32 secret sensitive?: Completely — anyone holding it can generate your codes forever. Store it like a password, and enrol it in an authenticator app rather than pasting it around.

Next steps

Open the OTP code generator tool

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