Bcrypt Hash Generator & Checker
Hash a password with bcrypt at a chosen cost, or verify a password against an existing bcrypt hash. Reads the cost and salt from a hash. Runs in your browser.
Bcrypt is a password-hashing function built to be slow, which makes brute-force attacks expensive. Each hash includes a random salt and a cost factor that sets how much work is required. This tool hashes a password at a cost you choose and verifies a password against an existing bcrypt hash — all in your browser.
How to use this tool
- Choose Hash or Verify.
- To hash, enter a password and pick a cost (10 is a sensible default).
- To verify, paste the password and the stored bcrypt hash.
- Copy the hash, or read whether the password matches.
Formula
A bcrypt string looks like $2b$10$<22-char salt><31-char hash>. The number after the prefix is the cost: the key-setup runs 2^cost times, so each step up doubles the work.
Example
Verifying the password "password" against $2a$04$AJ6PtAr3D6awLUS/tLJ2leWsZluJCrEcZo2CplM6hCgKCtAZvi6qe reports a Match and a cost of 4.
Frequently asked questions
What cost should I use?
A cost of 10–12 is common for web logins. Higher is more secure but slower; pick the highest value your server can tolerate for each login.
Why does the same password hash differently each time?
Because bcrypt generates a new random salt for every hash. Verification works because the salt is stored inside the hash string itself.
What is the 72-byte limit?
Bcrypt only processes the first 72 bytes of a password. Longer passwords are truncated, so very long passphrases should be pre-hashed before bcrypt in some designs.
Last updated:
Page address with these inputs: https://kakao.mobile/tools/bcrypt-generator/
Cite or embed this tool
kakaoCalc. (2026, November 8). Bcrypt Hash Generator & Checker. https://kakao.mobile/tools/bcrypt-generator/
“Bcrypt Hash Generator & Checker.” kakaoCalc, 8 Nov. 2026, kakao.mobile/tools/bcrypt-generator/.
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