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Two local-only measurements

Password Strength Checker & Entropy Calculator

Check a typed password for predictable patterns or calculate the theoretical entropy of a randomly generated password specification.

Check a password

Type a password below for instant feedback. Avoid testing a password you currently use.

Waiting for input0 estimated bits

Enter a password to see local-only feedback.

Your password stays privateWe check it only in this browser and never send or save what you type.

Password Entropy Calculator

Describe a password selected uniformly at random. This calculator does not inspect or require the password itself.

16
Every position must be independently selected from the complete pool for the theoretical result to apply.
Character pool used for every position
104.9 theoretical bits94-character pool
—possible combinations
—average exhaustive guesses
—equivalent random-word selection
Theoretical entropy is not a score for human-created passwords. Names, quotations, substitutions, reused values, and other patterns can make a password far easier to guess than this formula suggests.

Strength estimate versus entropy calculation

These are different measurements. The strength checker uses a local pattern-aware estimator for a value someone created. The entropy calculator uses an exact search-space formula for a password generated by a documented random process.

How password entropy is calculated

For independently selected random characters, theoretical entropy is length × log₂(character pool size). A 12-character password drawn uniformly from 94 printable non-space ASCII characters has about 78.7 bits. That means approximately 4.76 × 1023 possible results before accounting for any generator constraints.

Why the formula can overstate a human password

The formula assumes every position was independently and uniformly selected from the declared pool. A person choosing a phrase, keyboard pattern, name, date, or predictable substitution does not follow that process. Use the typed-password checker for pattern-aware feedback and the calculator only when you know how the password was generated.

Why crack time is not shown

Crack-time estimates depend heavily on the account's rate limits, password hashing algorithm, work factor, attacker hardware, and whether the attacker is guessing online or against a stolen verifier. This calculator reports the transparent search space instead of presenting one speculative time as universal.

Length and uniqueness matter

Longer random values create more combinations, but a reused password can still be exposed by another site. Use a different credential for every account. Read the strong-password guide for a current, repeatable creation and storage process.

Why this is not a breach check

Determining whether an exact password has appeared in a breach requires a separate service and privacy design. This page deliberately performs local analysis only.