Password Generator
Generate strong random passwords locally in your browser, with entropy scoring.
About Password Generator
A password is built by randomly selecting characters from the pool you enable (lowercase always on, plus optional uppercase, numbers, and symbols). Longer passwords and larger character pools mean more entropy — a measure of how hard the password is to guess.
Formulas
Password entropy
Entropy (bits) = Length × log₂(charset size)
- H
- Entropy in bits
- L
- Password length in characters
- N
- Number of distinct characters in the pool (charset size)
Total possible passwords
Possible passwords = charset size ^ length
- N
- Charset size
- L
- Password length
Worked example
With the default values below, Password Generator returns Your Password of IrcQS=WpJAv79}7z. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Lengthaccepts 4–64 chars
- 16 chars
- Include Uppercaseone of Yes, No
- Yes
- Include Numbersone of Yes, No
- Yes
- Include Symbolsone of Yes, No
- Yes
- Regenerate (change to make a new one)accepts 0–999,999
- 0
Results
- Your Password
- IrcQS=WpJAv79}7z
- Entropy (bits)
- 103
- Character Pool
- 85
Step by step
- 1Build the character pool from enabled classes= 85 characters
- 2Entropy = length × log₂(charset size)= 103 bitsEach additional character adds log₂(charsetSize) bits; each additional class adds log₂((old + new) / old) bits per character.
- 3Password generated16-character password drawn from 85-symbol pool using crypto.getRandomValues.
Assumptions and limits
- The result is derived only from the 5 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to whole numbers, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How long should my password be?
Aim for at least 12–16 characters with a mix of character types. Longer is stronger; 16+ with symbols is a solid default for important accounts.
Is this password stored anywhere?
No. Generation happens entirely in your browser and nothing is sent to or saved on any server.