What cost factor should I use for Bcrypt?

Cost factor 10 is the recommended default for most applications — it takes roughly 100ms to hash on modern hardware. Use 12 for high-security applications where you can afford ~400ms per hash. Use 4 only for testing. Increase the cost factor over time as hardware improves.

Can two identical passwords produce different Bcrypt hashes?

Yes. Bcrypt automatically generates a unique random salt for each hash, so the same password will produce a different hash every time. This is by design — it prevents rainbow table attacks. When verifying, Bcrypt extracts the salt from the stored hash automatically.

Is my password sent to a server when I use this tool?

No. All Bcrypt hashing and verification runs entirely in your browser using the bcryptjs library. Your passwords are never transmitted to any server.

How do I verify a Bcrypt hash?

Enter the original password in the password field, paste the stored Bcrypt hash in the verification field, and click Verify Hash. The tool will compare them and tell you if they match.

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Bcrypt Hash Generator

Hash and verify passwords using Bcrypt — the industry standard for secure password storage.

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Bcrypt Password Hashing

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Bcrypt is designed for hashing passwords. Higher rounds = slower = more secure. Default of 10 is a good balance for most applications.

Password / Text *

Work Factor (rounds)

Bcrypt Hash (for verification)

Output

Bcrypt hash or verification result will appear here…

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Frequently Asked Questions

What is Bcrypt and why use it for passwords?

Bcrypt is a password hashing function designed to be slow, making brute-force attacks impractical. Unlike SHA-256 (fast by design), Bcrypt's adjustable cost factor lets you increase hashing time as hardware improves. Always use Bcrypt, Argon2, or PBKDF2 for passwords — never plain MD5 or SHA.

What cost factor should I use?

Cost 10 is recommended for most applications (~100ms per hash). Use 12 for high-security scenarios (~400ms). Use 4 for testing only. Increase the cost factor as hardware gets faster — re-hashing passwords at login time is the standard approach.

Why does the same password produce different hashes each time?

Bcrypt automatically generates a unique random salt for every hash. The salt is embedded in the hash output, so verification works without storing the salt separately. This prevents rainbow table attacks.

Is my password sent to a server?

No. All Bcrypt hashing runs entirely in your browser using the bcryptjs JavaScript library. Your passwords are never transmitted anywhere.

What is the maximum password length for Bcrypt?

Bcrypt silently truncates input at 72 bytes. If you need to hash longer passwords, pre-hash with SHA-256 first. This limitation is a known quirk of the original Bcrypt specification.

Should I use Bcrypt or Argon2?

Both are excellent choices. Argon2 (winner of the Password Hashing Competition) is newer and more resistant to GPU attacks. Bcrypt is battle-tested with 25+ years of use. If your platform supports Argon2, prefer it. Bcrypt is a solid fallback with wide library support.