Bcrypt Generator
Generate bcrypt password hashes and verify strings against existing hashes, entirely in your browser. Plain text never leaves your device.
Bcrypt Generator & Checker
Generate strong passwords or verify existing bcrypt hashes securely in your browser.
Generate Hash
Higher rounds = slower generation, but significantly harder to crack via brute-force.
Verify Hash
What is bcrypt?
Bcrypt is a password hashing function designed for security over speed — intentionally slow to make brute-force attacks computationally expensive. It automatically includes a random salt to prevent rainbow table attacks and is the standard for storing passwords in web applications. Unlike MD5 or SHA-256, which are designed to be fast and can process billions of hashes per second on modern hardware, bcrypt's deliberate slowness makes it resistant to bulk password cracking.
This tool uses the bcryptjs library, running entirely in your browser. Your plain text password is never transmitted to any server — making it safe to use with real passwords during development or testing. You can generate new hashes and verify strings against existing hashes without any risk of interception.
How to Use the Bcrypt Generator
- Choose your mode — select "Hash" to generate a new bcrypt hash from a plain text string, or "Verify" to check whether a plain text string matches an existing hash.
- Enter your plain text — type or paste the password or string you want to hash; it stays in your browser and is never transmitted anywhere.
- Set the cost factor — choose a cost factor between 10 and 14; cost 10 is the minimum for production use, cost 12 is the current recommendation. Higher values add more protection at the cost of hash generation time.
- Copy the hash — click copy to grab the bcrypt hash string, ready to store in your database or use in your test fixtures.
What are Salt Rounds?
The cost factor (also called salt rounds or work factor) controls how computationally expensive bcrypt is to run. A cost of 10 means the algorithm performs 210 = 1,024 iterations. A cost of 12 means 212 = 4,096 iterations — four times slower than cost 10. Each increment doubles the work, so cost 14 is 16× slower than cost 10. This exponential scaling is what allows bcrypt to remain secure as hardware gets faster over time — you simply increment the cost factor.
Who Is This For?
- Developers verifying their bcrypt implementation before deploying it — generate a hash here, then confirm your application verifies it correctly.
- Security engineers generating test hashes for development and staging environments, where a known plaintext/hash pair is needed for fixtures or seed data.
- Anyone learning how password hashing works and wanting to see how the cost factor and salt affect the output string in practice.
Key Benefits
- Privacy — plain text runs through bcryptjs entirely in your browser and is never transmitted anywhere; this is one of the strongest privacy guarantees on the site.
- Free — no account, no subscription, no rate limiting.
- No account required — generate and verify hashes immediately with no setup.
- Adjustable cost factor — test cost factors from 10 to 14 to understand the performance trade-off before choosing a value for your application's hardware.
Common Bcrypt Mistakes
- ✗Using a cost factor below 10 in production — cost factors under 10 hash too quickly, making brute-force attacks feasible on modern hardware; the OWASP minimum recommendation is 10, with 12 preferred for new applications.
- ✗Hashing passwords that are already hashed — if your application pre-hashes before passing to bcrypt, the second hash loses its entropy guarantee; bcrypt should always receive the raw plaintext password.
- ✗Using bcrypt for data other than passwords — bcrypt is a KDF designed for low-throughput password storage; for encrypting large data or generating tokens, use AES-GCM or HMAC-SHA256 instead.
For a complete authentication security workflow, pair bcrypt hashing with our Password Generator to create strong plaintexts before hashing, and the JWT Decoder for inspecting authentication tokens in your application.
Worked Example: Choosing the Right Cost Factor
A Node.js API handles login for a SaaS app. The team needs to pick a cost factor that is secure against brute-force but fast enough to not frustrate users. Here's how the trade-off looks on a modern server:
| Cost Factor | Iterations | Hash time (modern server) | Brute-force rate (GPU) |
|---|---|---|---|
| 10 | 1,024 | ~65ms | ~20k hashes/sec |
| 12 ✓ recommended | 4,096 | ~250ms | ~5k hashes/sec |
| 14 | 16,384 | ~1,000ms | ~1.2k hashes/sec |
At cost 12: a user waits ~250ms at login — imperceptible. An attacker brute-forcing a stolen hash database can try 5,000 passwords per second per GPU. At cost 14, that drops to 1,200/sec — 4× slower for the attacker, but login takes a full second, which degrades UX noticeably. Cost 12 is the standard recommendation for new applications as of 2024.
How This Tool Compares
| Feature | This Tool | bcrypt.online | cmd line (htpasswd) |
|---|---|---|---|
| Runs in browser (no server) | ✓ bcryptjs | ✗ server-side | ✓ local |
| Verify mode (check hash) | ✓ | ✓ | ✗ |
| No account required | ✓ | ✓ | ✓ |
| Safe for real passwords | ✓ (never leaves device) | Risk (server logging) | ✓ |
Last updated: April 2026. Cost factor benchmarks based on bcryptjs running on a 2024 cloud VM; performance will vary by hardware.
For the authoritative guidance on password storage, hashing algorithms, and cost factor recommendations, see the OWASP Password Storage Cheat Sheet.
Common Use Cases
Generating a test hash to seed a development database with a known password. Verifying that a password your application is hashing matches the expected bcrypt format before deploying to production. Comparing hash generation time at different cost factors to find the right balance for your server's hardware — aim for under 250ms per hash on your login endpoint. Teaching a team or class how bcrypt salting and key stretching work by showing the same password producing different hashes on each run.
Frequently Asked Questions
What is bcrypt? ↓
Bcrypt is a password hashing function designed for security over speed — intentionally slow to make brute-force attacks computationally expensive. It automatically includes a random salt to prevent rainbow table attacks and is the standard for storing passwords in web applications. Unlike MD5 or SHA-256, which are designed to be fast, bcrypt's deliberate slowness makes it resistant to bulk password cracking.
Is this bcrypt generator free? ↓
Yes, completely free. The hashing runs entirely in your browser using the bcryptjs library — no server, no account, no limits. Your plain text password is never transmitted anywhere, making this safe to use with real passwords during development.
What is a salt in bcrypt? ↓
A salt is a randomly generated string added to the password before hashing, so two users with the same password produce different hashes. The salt is stored alongside the hash — embedded directly in the output string — and used during verification to reproduce the correct hash. This prevents rainbow table attacks, where an attacker pre-computes hashes for common passwords.
What is the cost factor in bcrypt? ↓
A number that controls how many iterations of hashing are performed — each increment doubles the computation time. Cost factor 10 is the minimum for modern applications; 12 is the current recommendation. Higher values slow down both attackers and your login verification, so choose a value based on how long your server hardware can tolerate during a login request — typically aim for under 250 milliseconds per hash.
Can I reverse a bcrypt hash to get the original password? ↓
No. Bcrypt is a one-way function — there is no mathematical way to extract the original password from a hash. The only way to crack a bcrypt hash is to guess passwords and hash each guess until one matches, which the cost factor makes prohibitively slow. This is why bcrypt is appropriate for password storage, while reversible encryption is not.
What is the difference between bcrypt and SHA-256? ↓
SHA-256 is designed to be fast — it can hash billions of strings per second on modern hardware, making it easy to brute-force a list of stolen passwords. Bcrypt is designed to be slow and scales with the cost factor. SHA-256 is appropriate for checksums and data integrity verification; bcrypt (or Argon2) is appropriate for password storage where attacker speed must be constrained.
The calculators on The Simple Toolbox are for educational and planning purposes only. Results are estimates based on your inputs and standard assumptions — they are not financial, legal, or tax advice. Consult a qualified professional before making significant financial decisions.
Free Tools Alert
Join 10,000+ creators. Get our newest productivity tools, templates, and calculators directly to your inbox every month.
No spam. One-click unsubscribe.