Seed phrase strength calculator
How many possible 12 or 24-word seed phrases are there, and how long would it take to guess one? Pick the number of words to see. It never asks for your words. Free, no sign-up, nothing leaves your browser.
- 1Type in your own numbers
- 2The tool works it out
- 3See the answer clearly
For phrases made at random by a wallet using the BIP39 standard. A phrase someone chose themselves, or one with words left out, can be far weaker. Never type your real seed phrase into any website.
Where the strength comes from
Most wallets follow a standard called BIP39, which picks each word from a fixed list of 2,048. A 12-word phrase holds 128 bits of randomness and a 24-word phrase 256 bits; the last word also carries a small checksum that catches typing mistakes. Every extra bit doubles the number of possible phrases.
Why guessing doesn't work, and what does
Even at speeds far beyond any real computer, guessing a randomly generated 12-word phrase would take vastly longer than the age of the universe. That is why thieves don't guess seed phrases: they trick people into typing them into fake websites or apps, or find them stored in photos, emails or cloud notes. Never enter your real seed phrase anywhere, including this page, which doesn't ask for it.
See it happen
Your own money app- 1Name it and pick your colours
- 2Choose what it does
- 3Launch when you are ready
Try it
Name your platform and watch it come to life
Type a name, tap a colour and pick what it does. The phone changes as you go.
Colour
What it does
Design and preview your whole platform free, then launch when you are ready.
Run your own crypto app
With a custodial service, the provider holds the keys for you and there's usually no seed phrase to manage. SendPay crypto platforms let your customers buy, sell and hold crypto, with assets held with regulated partners.