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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How Bcrypt Hashing Works

Bcrypt is a password hashing algorithm designed to be intentionally slow. Unlike SHA-256 which executes in microseconds, Bcrypt's cost factor lets you control how long each hash takes — making brute-force attacks exponentially harder as hardware improves.

Each Bcrypt hash includes a random salt automatically, so two identical passwords always produce different hashes. This prevents rainbow table attacks. This tool uses bcrypt.js running entirely in your browser — no passwords are transmitted anywhere.

Common use cases

Hashing passwords before storing them in a database
Verifying a plaintext password against a stored Bcrypt hash
Testing Bcrypt cost factors to balance security and performance
Learning how password hashing works in web applications

Bcrypt Online Compatibility

This bcrypt generator creates standard hashes in the $2a$ format used by many Node.js, PHP, Python, Ruby, and Java libraries. The generated hash includes the algorithm marker, cost factor, salt, and password hash in one string.

Use the verification field to test a password against an existing bcrypt hash from a database. This is useful when checking login bugs, migrating password hashes, or comparing bcryptjs output with server-side bcrypt implementations.

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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.