Calculate password entropy in bits.
Password Entropy Calculator runs in the page as you use it. There is no input to submit and no result to fetch, because the whole thing happens on this side of the wire.
The parsing, the maths and the formatting all happen in JavaScript on this page. No request carries your input anywhere, because there is no endpoint for one to reach.
You will find it under Passwords, alongside 7 other tools for the same sort of job.
Computes standard and Shannon entropy, character pool analysis, and security level assessment.
MyP@ssw0rd!2024
=== Password Entropy Analysis === Password length: 15 characters Unique characters: 12 Character pool size: 95 Standard entropy: 98.55 bits Shannon entropy: 52.60 bits Bits per character: 6.57 Security level: Very Good (strong) Key equivalent: DES-equivalent or weaker Character classes used: Lowercase (a-z): Yes (+26) Uppercase (A-Z): Yes (+26) Digits (0-9): Yes (+10) Symbols: Yes (+33) Spaces: No Unicode: No Entropy thresholds: 28 bits = Weak [PASS] 40 bits = Fair [PASS] 60 bits = Good [PASS] 80 bits = Strong [PASS] 128 bits = Excellent [FAIL]
Yes. It is JavaScript running in this tab, so once the page has loaded it needs nothing further from the network. Put the machine in flight mode and it carries on. Nothing you do here is sent anywhere, because there is nowhere for it to go.
No. Reload the page and it starts from nothing. There is no account, no saved state and no cookie holding your last session. That is a deliberate trade: it cannot lose your data because it never keeps any.
Timing comes from performance.now(), the high resolution clock the browser provides, rather than from setInterval, which drifts by a few milliseconds every tick and compounds over minutes. What can still shift things is the browser throttling a tab in the background, so leave it visible if the timing matters.
Where a sound makes sense, it is generated with the Web Audio API rather than loaded as a file, so there is nothing to download and nothing to block. Browsers refuse to start audio until you have interacted with the page, which is why the first press is what switches it on.
Yes. The controls are sized for touch and the layout collapses to one column on a narrow screen. Bear in mind that a phone locking its screen will suspend the page, and timing stops with it.