Counter-based one-time code
Calculate a counter-based HOTP code from a Base32 secret and a counter value.
Your saved tools stay in this browser.
Counter-based one-time code — workspace
Loading your tool…
How to use: Counter-based one-time code
Start with the example, or replace it with your own values.
Review Secret key, Counter, Code digits (6 or 8), then select “Get result”.
Read the result, then copy or download it. Edit any input to try again.
What you can do
- Calculate a counter-based HOTP code from a Base32 secret and a counter value.
What you get
- A result you can review, copy or download. Numeric tools show labeled calculations; text tools show the transformed output.
What you need
- Secret key
- Enter your own value; public example credentials must not be used as real secrets.
- Counter
- Enter a whole number (0–1000000000).
- Code digits (6 or 8)
- Enter a whole number (6–8).
Try an example
- Counter
0
- Code digits (6 or 8)
6
Good to know
- RFC 4226/6238, SHA-1, Base32 secret. TOTP uses 30-second steps and the entered Unix time. Example secrets are public; replace them.
- Examples are public demonstrations. Replace example passwords and keys before using an output for a real purpose.
Your work stays on your device
Your files and entered values are processed in your browser and are not uploaded for processing. The website and any required processing engines still download from the site.
Questions & answers
Is Counter-based one-time code free?
Yes. Counter-based one-time code is free to use and does not require an account.
Are my files or entered values uploaded?
Your files and entered values are processed in your browser and are not uploaded for processing. The website and any required processing engines still download from the site.
What result can I save?
A result you can review, copy or download. Numeric tools show labeled calculations; text tools show the transformed output.
What should I check before using the result?
RFC 4226/6238, SHA-1, Base32 secret. TOTP uses 30-second steps and the entered Unix time. Example secrets are public; replace them. Examples are public demonstrations. Replace example passwords and keys before using an output for a real purpose.