Strong Password Generator - XKCD Passphrases & Entropy Tool

Strong password generator for random passwords or XKCD passphrases. See entropy and crack-time estimatesโ€”secure, client-side only. Generate yours now.

Entropy

********

Entropy: 0.00 bitsCrack time: 0.0 sec

Estimated crack time

CPU
GPU
Cluster

Passwords are generated locally and disappear on refresh.

How to Use

  1. Choose Random or Memorable mode.
  2. Tune length, character sets, word count, or separators.
  3. Click Generate and review entropy + crack-time.
  4. Copy your password, or lock it to prevent regeneration.

Core Features

  • Generate high-entropy random passwords with custom character sets.
  • Create XKCD-style memorable passphrases that are easy to recall.
  • Analyze password entropy and show a clear strength rating.
  • Estimate crack time under different attacker speeds (CPU/GPU/cluster).
  • Exclude ambiguous characters (O/0, l/1) for safer manual entry.
  • Protect privacy with cryptographic, client-side randomness only.

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Calculation Logic

  • Use crypto.getRandomValues for cryptographic randomness.
  • A common entropy approximation is H=Lโ‹…logโก2(N)H = L \cdot \log_2(N).
  • Passphrases gain strength from the size of the word pool and number of words.

FAQ

  • Is it free?
    • Yes.
  • Is my password uploaded or stored?
    • No. Passwords are generated locally and disappear on refresh.
  • Why are passphrases like โ€œcorrect-horse-batteryโ€ better?
    • Theyโ€™re easier to remember while still high-entropy and hard to brute-force.
  • How is entropy calculated? (Technical)
    • A common approximation is H=Lโ‹…logโก2(N)H = L \cdot \log_2(N), where L is length and N is the character set size.
  • Why does length often beat โ€œmore symbolsโ€?
    • Increasing length expands the search space exponentially, usually improving security more than adding complexity alone.