Measure password strength instantly with a free entropy calculator that shows how many bits of unpredictability your password has.
Learn how entropy helps measure password strength and why it matters for online security.
Entropy measures how unpredictable a password is in bits. One bit means two possible outcomes, two bits means four, and the number grows quickly as the password gets longer and more varied. That is why a few extra characters can raise entropy significantly.
Entropy is calculated from the number of possible combinations, and a strong target is often 80+ bits for everyday accounts. A longer password with diverse characters is generally much harder to guess than a shorter or more predictable one.
While entropy is mathematical, password strength also depends on avoiding predictable patterns and dictionary words. A random 10-character password can be stronger than a 12-character password that uses obvious structure.
Our calculator shows entropy, but a password created by a generator is usually more secure than one that was invented manually.
For everyday accounts, 60+ bits is a useful baseline. For sensitive accounts such as email or banking, 80+ bits is a better target, while master passwords should often reach 128+ bits. Use our entropy calculator to compare your results, generate stronger alternatives with our password generator, and estimate cracking time with our time to crack estimator.
Calculate actual entropy in bits based on the character set and length you enter.
See the total number of possible password combinations for your selected character set and length.
Get practical recommendations based on the entropy level and the type of account you are protecting.
Questions about password entropy and how to interpret the results.
80+ bits of entropy is generally strong for most accounts. For critical accounts such as email or banking, 100+ bits is a stronger target, and master passwords should often reach 128+ bits.
Entropy is mathematical and is based on the character set and length of the password. Real-world strength also depends on patterns and dictionary words, so a truly random password can still be stronger than a longer one with obvious structure.
No, higher entropy is usually better for security. The main tradeoff is memorability if you are not using a password manager. For most accounts, a password manager is the easiest way to keep strong, high-entropy passwords.
All processing happens locally in your browser. No data is stored or transmitted.