Securely generate and verify Bcrypt hashes completely locally in your browser.
Bcrypt is a password hashing function designed by Niels Provos and David Mazières in 1999, based on the Blowfish cipher. Unlike fast hashing algorithms like MD5 or SHA-256 that can compute billions of hashes per second, Bcrypt is intentionally slow and computationally expensive—this is by design. The key innovation of Bcrypt is its adaptive cost factor (salt rounds): as hardware becomes more powerful, you can increase the cost factor to make hashing proportionally slower, keeping it resistant to brute-force attacks. Each Bcrypt hash includes a randomly generated salt embedded in the output, the cost factor, and the resulting 184-bit hash, making it impossible for attackers to use precomputed rainbow tables.
Our browser-based Bcrypt tool is built for developers who need to quickly generate or verify password hashes during development without spinning up a local server or writing throwaway scripts. You can test different cost factors to find the right balance between security and performance for your application. Since the tool runs entirely in your browser using a JavaScript implementation of Bcrypt, your passwords and hashes are never transmitted to any server. The verify mode lets you paste a plaintext password and an existing hash to confirm whether they match—invaluable when debugging authentication issues.
The salt rounds parameter (also called the cost factor) determines how computationally intensive the hashing process is. It is expressed as a power of 2: a cost factor of 10 means 2^10 (1,024) iterations of the key expansion algorithm. Each increment doubles the computation time. At cost factor 10, hashing typically takes around 100ms on modern hardware. At cost factor 12, it takes roughly 300-400ms. For most web applications, a cost factor between 10 and 12 provides a good balance between security and user experience.
For most web applications in 2026, a cost factor of 12 is recommended. This provides strong security while keeping hash computation under 400ms. For high-security applications like financial services, consider cost factor 13-14. Always benchmark on your production hardware.
MD5 and SHA-256 are general-purpose hash functions designed for speed. A modern GPU can compute billions of SHA-256 hashes per second, making brute-force attacks feasible. Bcrypt is purposely slow and includes a built-in salt, making each hash unique even for identical passwords.
Yes, and this is intentional. Bcrypt generates a unique random salt for each hash operation. To verify a password, you must use the verify function, which extracts the salt from the stored hash and re-hashes the input with that specific salt for comparison.