Developer Tools
Password Strength Calculator
Password Strength: password Strength Calculator estimates strength from length and character variety, reporting the search-space size and a crack-time estimate. Worked through below with real figures, and the calculator repeats the working on your own inputs — free, on-device, instant.
Password Strength Calculator is a browser-based way to gauge a password's strength. Feed it your password to check and it computes a strength score and crack-time estimate on the spot, keeping your data local.
Runs locally in your browser and nothing you type is uploaded. Do not paste real production passwords; use this for estimates only. Strength and entropy are heuristic and do not check breach databases.
About this tool
Password Strength Calculator estimates strength from length and character variety, reporting the search-space size and a crack-time estimate. That is the whole of the calculation — the mistakes happen in the inputs. It is a light-hearted toy — fine for a laugh or a quick what-if, not for decisions that matter. Worked example: Length matters most: a 16-character mixed password has far more combinations (95 16 ) than an 8-character one, so it resists brute-force vastly longer. Use the calculator with your own figures; it runs entirely on your device.
How to use
- Enter a sample password to check.
- Let the checker weigh length and variety.
- Run it to score common patterns too.
- Read the rating and any suggestions.
Why use the Password Strength Calculator
Instant
Each result is computed on your device the moment you run the tool.
Private
The text and numbers you enter stay in your browser and are never uploaded.
Free
No signup and no paywall to use any tool in this set.
Works offline
Once the page has loaded it keeps working on a weak or dropped connection.
Built for developers
Plain inputs and outputs you can copy straight into code, configs, or notes.
Honest by design
Conversions and heuristics are for everyday and learning use; verify security-critical output with trusted, official tools.
Common uses
Use it when checking a password's strength
Use it for choosing a memorable but strong key
Use it when auditing account security
Password Strength in a security review
Use it for password-policy decisions
Use it when onboarding a new account
Technical notes
Password Strength Calculator estimates strength from length and character variety, reporting the search-space size and a crack-time estimate.
Results are reference values; validate against your own environment before relying on them in production.
Nothing you type is uploaded — the calculation happens entirely on your device.
Worked example
Length matters most: a 16-character mixed password has far more combinations (9516) than an 8-character one, so it resists brute-force vastly longer.
FAQ
Does the strength check look up breaches?
No. It does not contact any breach database; it only rates length, variety, and obvious common patterns.
Why is a long mixed password still rated low sometimes?
If it starts with a very common word such as the word password, the score is reduced because that base is easy to guess.
What raises the strength score most?
Greater length and using more character types, such as upper case, lower case, digits, and symbols together.
Is it safe to enter my real password?
Please use an example instead; although it runs locally, the tool is intended for estimates and teaching.