AnyTool
Your files never leave your device. All processing happens locally in your browser.

How do I generate a strong, secure password?

Open AnyTool Password Generator, pick a length of 16 or more characters with uppercase, lowercase, digits and symbols, and a strong random password is created instantly using your browser’s crypto-secure randomness. Or switch to passphrase mode for several random words that are easy to remember. A live meter shows the entropy in bits and an estimated crack time. Nothing is uploaded.

  • Cryptographically secure randomness (Web Crypto, no modulo bias) — never Math.random
  • Random passwords (4–128 chars) or memorable diceware-style passphrases
  • Exclude look-alike characters, require one of each set, no repeats, custom symbols
  • Live strength meter: entropy in bits, label and offline crack-time estimate
  • Bulk-generate up to 200 at once · 100% in your browser, nothing uploaded

What is

Password Entropy

Password entropy measures how unpredictable a password is, expressed in bits. For a uniformly-random secret it equals length multiplied by the base-2 logarithm of the character-pool size (or number of words times the log of the word-list size for a passphrase). Each extra bit doubles the number of guesses an attacker needs, so more bits means a stronger password.

Generators

Related terms

Diceware passphraseCrypto-secure randomBrute-force attackTwo-factor authentication

Frequently Asked Questions

At least 12–16 characters. Length matters more than complexity, and 16+ random characters is strong for almost any account.

Length is the single biggest factor in password strength. NIST guidance favours longer passwords over forced symbol rules, because each extra character multiplies the work an attacker must do. Aim for at least 12 characters, and 16 or more for important accounts like email, banking or your password-manager vault. A 16-character random password mixing letter cases, digits and symbols carries roughly 100 bits of entropy, which is far beyond what offline attackers can brute-force.

A passphrase can be just as secure if it has enough random words. Five random words is around 50–65 bits; six or seven words is very strong.

A diceware-style passphrase made of several truly random words can match a random password for strength while being far easier to remember and type. Each word from a list of about a thousand words adds roughly 10 bits of entropy, so five words give around 50 bits and six or seven words reach the 60–70-bit range that is solid for everyday use. The key is that the words must be chosen randomly by the computer, not picked by you — AnyTool draws each word with crypto-secure randomness.

No. Every password is generated locally in your browser with crypto-secure randomness and is never uploaded, logged or stored.

AnyTool Password Generator runs entirely in your browser. It uses the Web Crypto API (crypto.getRandomValues) with rejection sampling to produce unbiased, cryptographically secure passwords without any server round-trip. Nothing you generate is sent anywhere, saved, or tracked — close the tab and the passwords are gone. The page even works offline after the first load.

It uses the operating system’s secure random source (Web Crypto) instead of Math.random, and avoids modulo bias with rejection sampling.

A secure generator must draw randomness from a cryptographically secure source — in the browser that is crypto.getRandomValues, which is seeded by the operating system — rather than Math.random, whose output is predictable. It also has to map those random numbers onto the character set without bias: AnyTool uses rejection sampling, discarding values that would skew the distribution, so every character is exactly equally likely. That combination is what makes the generated passwords genuinely unpredictable.

Detailed Explanation

Methodology

How the Password Generator Works

AnyTool Password Generator produces every secret in the browser using the Web Crypto API. Random integers come from crypto.getRandomValues, and they are mapped onto the chosen character set with rejection sampling — values that would fall outside an even multiple of the pool size are discarded — so there is no modulo bias and every character is exactly equally likely. Math.random is never used for secret material. Random passwords can be 4 to 128 characters with any mix of uppercase, lowercase, digits and symbols, plus options to exclude look-alike characters, require at least one of each selected set, forbid repeats, and supply a custom symbol set.

  • Randomness from crypto.getRandomValues (CSPRNG), not Math.random
  • Rejection sampling removes modulo bias — uniform character choice
  • Random password length 4–128 with selectable character sets
  • Options: exclude ambiguous, require-each-set, no-repeat, custom symbols
  • All generation is client-side JavaScript — no server round-trip
How It Works

Passphrase Mode and Entropy

In passphrase mode the generator picks several words at random from a bundled clean, family-friendly word list of roughly a thousand common words, joining them with a chosen separator and capitalization in the diceware style. Strength is reported as Shannon entropy in bits: length × log2(pool size) for character passwords, or words × log2(list size) for passphrases — each word contributing about ten bits. The page maps entropy to a label (very weak through very strong) and to an estimated offline crack time, treating roughly 60 bits as solid for everyday accounts and 80-plus bits as appropriate for high-value accounts.

  • Passphrases are random words from a clean ~1,000-word list
  • Each word adds about 10 bits of entropy (log2 of the list size)
  • Entropy = length × log2(pool) or words × log2(list size)
  • ~60 bits is solid for most accounts; 80+ bits for high-value accounts
  • Separator, capitalization and an optional digit/symbol are configurable
Privacy & Security

Privacy, Estimates and Offline Use

Because all generation happens in the browser, no password is ever sent to a server, logged, or stored — closing the tab discards it, and the page works offline once cached. The displayed crack time is an estimate that assumes a uniformly-random secret and a fast offline attacker making about a trillion guesses per second against an unsalted fast hash; with a slow hash such as bcrypt or Argon2, or with online rate-limiting, real attacks are far slower. The figures are an honest guide rather than a guarantee, and the tool recommends a password manager, two-factor authentication, and never reusing passwords.

Password generation: in-browser (AnyTool) vs typical online generators
CapabilityAnyToolTypical online generators
RandomnessWeb Crypto CSPRNG, rejection samplingSometimes Math.random / server-side
ProcessingRuns in your browserOften server-side
Passphrase modeYes, clean diceware-style word listOften passwords only
Strength meterEntropy bits + label + crack-time estimateOften a vague bar or none
Advanced optionsExclude look-alikes, require-each, no-repeat, custom symbolsUsually basic toggles
Bulk generateUp to 200, copy-all / download .txtRare
PrivacyNever uploaded, not stored, works offlineMay transmit or log
Cost / signupFree, no signupOften ad-heavy or gated

AnyTool generates every password locally with crypto-secure randomness and uploads nothing.