Question 1

Is Entropy free to use?

Accepted Answer

Yes. Entropy is completely free, requires no account, and has no ads or paywalls.

Question 2

Does Entropy send my passwords anywhere?

Accepted Answer

No. Entropy is local-only. Every password and passphrase is generated and analyzed entirely in your browser using the Web Crypto API. Nothing you type or generate is ever transmitted, stored, or logged on a server.

Question 3

How does Entropy generate secure passwords?

Accepted Answer

Entropy uses the browser’s cryptographically-strong random number generator (crypto.getRandomValues) with unbiased rejection sampling — never Math.random — so every character or word is uniformly random and unpredictable.

Question 4

What is password entropy and why does it matter?

Accepted Answer

Entropy, measured in bits, quantifies how unpredictable a password is. Each additional bit doubles the number of guesses an attacker needs. More bits means exponentially longer crack times. Entropy shows the exact bit count and estimated time to crack for any password.

Question 5

Are passphrases stronger than random passwords?

Accepted Answer

A passphrase of several random words can reach high entropy while staying far easier to remember and type than a random character string of equivalent strength. Entropy generates both so you can compare their entropy directly.

Question 6

Can I check the strength of a password I already have?

Accepted Answer

Yes. Switch to Analyze mode and paste any password to see its entropy in bits, a strength rating, estimated crack time, and a breakdown of its character composition — all computed locally in your browser.

Entropy — free, local-only password generator and strength analyzer