Cryptography & Security

Bcrypt Generator

Generate salted bcrypt hashes for test data, or check whether a plaintext password matches a stored hash.

Free & unlimitedRuns in your browserNo sign-up required

Generate Bcrypt Hash

Password string

Cost Factor (Rounds)

Verify Hash

Hash string to verify

Password to test

Bcrypt Password Hashing

Storing plain-text passwords is how companies end up in breach headlines. Storing them hashed with something fast, like MD5 or even plain SHA-256, isn't much better, because modern GPUs can try billions of guesses per second against a fast hash. Bcrypt exists specifically to fix that problem.

Slow by design

Bcrypt is a password hashing function built with one goal: be slow on purpose. It has a configurable "cost factor" (also called work factor or rounds) that controls exactly how much computation is needed to generate a single hash. Where SHA-256 might compute in microseconds, bcrypt is designed to take a noticeable fraction of a second. If a hash takes 200 milliseconds to compute, an attacker trying to brute-force a list of a million passwords per stolen hash goes from minutes to days.

Salts and rainbow tables

Bcrypt automatically generates and stores a random salt as part of the output hash, so two identical passwords never produce the same hash string. That defeats rainbow table attacks completely, since an attacker can't precompute hashes for common passwords and match them against a stolen database. The cost factor is stored inside the hash string itself, so you can raise it over time as hardware gets faster without breaking verification of older hashes.

Cost factor tuning

The typical cost factor recommendation as of 2026 sits between 10 and 12 for web applications, balancing security against login response time. Go higher and you start adding real, user-noticeable delay to every login. Go lower and you erode the protection bcrypt is built to provide. For anything handling sensitive accounts, financial data, or admin access, 12 is a reasonable floor.

The 72-byte limit

It's also worth knowing bcrypt has a quirky limitation: it silently truncates input passwords longer than 72 bytes. If your application accepts very long passphrases, that's worth testing for explicitly, since a 200-character password and a 72-character password could hash identically.

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How it works

Three steps, no setup

Choose a mode

Switch between hashing a new password and comparing one against an existing hash.

Set the cost factor

Higher rounds take longer to compute and are harder to brute-force.

Hash or verify

Copy the resulting hash, or see an instant match/no-match result.

Common questions

Frequently asked questions

What cost factor should I pick?

A work factor of 10-12 is a reasonable balance between security and response time for most web applications in 2026.

Why does the hash change every time?

Bcrypt generates a fresh random salt on every run, so two hashes of the same password will never match byte-for-byte — that is expected and correct.

Bcrypt Generator

Bcrypt Password Hashing

Slow by design

Salts and rainbow tables

Cost factor tuning

The 72-byte limit

Three steps, no setup

Choose a mode

Set the cost factor

Hash or verify

Frequently asked questions

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Bcrypt Password Hashing

Slow by design

Salts and rainbow tables

Cost factor tuning

The 72-byte limit