Password Crack Time Calculator
This estimates how long a brute-force search would take to try every password of a given length and character set. It is a teaching estimate of the math, not a rating of any password you use.
- Free
- Works offline after your first visit
- Saves on this device
- No sign-up
- Updated
How it works
The number of possible passwords is the character set size raised to the power of the length. Each extra character multiplies that count by the set size, which is why length matters most.
A search finds the password after trying about half of all possibilities on average. That half is divided by the guesses per second, then turned into years. The bits figure is the length times the base-2 logarithm of the set size.
Worked example
A password 12 characters long, drawn from 62 characters, has about 71.5 bits of randomness. At 1,000,000,000 guesses a second, a brute-force search would take about 51,117.1 years on average.
Questions
Does this check the password I use?
No. It shows the math for a length and character set you enter. It does not look at any password, and it cannot say how strong a real one is.
Why does guess speed matter?
Attackers test guesses at very different speeds, depending on the system they attack. Pick the speed you want to model, and the years change with it.
Does it count common words and patterns?
No. It assumes each character is picked at random. Words, names and familiar patterns are easier to guess than this estimate shows.
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