Password Strength Checker: The Complete Guide
See how strong a password really is. Type one in to get a strength rating, its entropy in bits, and an estimate of how long it would take to crack offline — all in your browser.
Who the Password Strength Checker is for
Anyone evaluating whether a password is strong enough before they rely on it.
How to use the Password Strength Checker
- Type your values into the fields above — pick your currency or units where the calculator offers them.
- Results update automatically as you type; there's no submit button and nothing is sent to a server.
- Adjust any input to compare scenarios, then copy the result with a single click.
How it works
Entropy ≈ length × log₂(character-pool size). The estimated offline crack time is 2^entropy ÷ a fast guessing rate (around 10 billion guesses per second).
Features
- Strength rating
- Entropy in bits
- Crack-time estimate
- Runs locally
How strength is measured
A password's resistance to guessing depends on its length and the variety of characters it uses, summarised as entropy in bits. More bits means exponentially more combinations to try. This checker estimates entropy and a worst-case offline crack time — but remember, dictionary words and predictable patterns are weak even when long, so avoid them.