Password generator
Generate configurable passwords with the browser’s secure RNG
Choose length, count and allowed characters, then generate. Enabling a character class allows it but does not guarantee it appears in every password.
Example
Input
Length: 20 · Count: 1 · Pool: a-z, A-Z, 0-9
Example result
20 randomly selected characters
Results vary each time. This example disables symbols and excludes 0, O, 1, l and I. The illustration is not a password to reuse.
Technical details & limits
crypto.getRandomValues supplies randomness, with rejection sampling to avoid modulo bias. Each position is sampled independently from the combined pool; enabling a class allows it but does not guarantee its appearance in every password. L×log2(N) is theoretical entropy under this model, not a guarantee of account security or cracking time.
About this tool
Generate random passwords locally with lengths of 4–128 characters, batches of 1–50, selectable character pools and ambiguous-character exclusion. Uses cryptographic randomness without sending generated values to a server.
Use cases
- Create a strong password for a new account.
- Generate a batch of one-off API keys or temporary tokens.
How to use
- Pick length, character classes and options.
- Click Generate. Passwords are generated only in your browser and are not uploaded.
Notes
Uses crypto.getRandomValues, not Math.random. Real strength depends on length and character mix. Do not paste passwords into untrusted third-party sites.
FAQ
- What password lengths and batch sizes does the generator support?
- This generator supports passwords from 4 to 128 characters and batches of 1 to 50 passwords. It obtains random values from the browser's cryptographic random interface and samples from the combined selected character pool. Check the target site's permitted length and symbols before using a result. Save accepted credentials in a password manager, and remember that selecting character categories does not force each category to appear in every generated password.
- Does selecting digits and symbols guarantee every password contains them?
- Selecting a character category allows characters from that category but does not guarantee their appearance in each password. Even a 16-character password sampled from 4 enabled categories may omit one category. Check the result and generate another if the destination requires particular classes. The selection controls the allowed pool, while the destination's acceptance policy is a separate requirement that this generator does not enforce through mandatory category placement.
- How is the password generator's theoretical entropy calculated?
- Theoretical entropy is password length multiplied by the base-2 logarithm of the character pool size. Using only 10 digits for a 16-character password gives approximately 53.2 bits under that model. The calculation assumes independent uniform sampling. It is not a guarantee of account security or a direct estimate of cracking time, which also depends on storage, attack conditions, reuse, and the system receiving the password.
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