Password Generator — Strong & Secure Password Creator
Generate strong, secure, random passwords instantly. Customize length and include uppercase, lowercase, numbers, and symbols.
💻 Developer Tools
✅ Free
By SwiftCalcTools Editorial Team · Formula verified
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How to Use Password Generator
- 1Enter the required values in the input fields above.
- 2Click the Calculate button or results update instantly as you type.
- 3View your results in the output panel below the inputs.
- 4Adjust any values to recalculate instantly.
Frequently Asked Questions
Strength is measured in bits of entropy: Entropy = length × log₂(charset size). A 16-char password with all character types (94 chars) has 16×log₂(94) ≈ 104 bits — excellent. For comparison: a 6-digit PIN = 20 bits (cracked instantly). An 8-char lowercase = 38 bits (cracked in hours). 80+ bits is considered strong against modern attacks.
Humans are predictable: we use common words, add numbers at the end, capitalize the first letter. Password crackers exploit these patterns. A random generator has no patterns — it uses cryptographically secure randomness (crypto.getRandomValues) making brute-force and dictionary attacks ineffective. Always use a password manager to store generated passwords.
Symbols significantly expand the charset (from 62 to 94 chars), adding ~0.7 bits per character. However, some systems reject certain symbols. If you don't know the policy, use letters + numbers for compatibility (charset 62), and compensate with a longer password — 20 alphanumeric chars (119 bits) beats 12 chars with symbols (78 bits).
Ambiguous characters are visually similar: 0 (zero) vs O (capital o), 1 (one) vs l (lowercase L) vs I (capital i). When you need to type or share a password verbally, excluding these reduces errors. For passwords stored in a password manager (copy-paste only), there's no reason to exclude them — shorter char exclusion = lower entropy per length.