dev/generator
Password & Entropy Calculator - Free & Instant | Smocky
Password & Entropy Calculator
Every character is drawn uniformly from the pool, so the Entropy is computed exactly from the draw rather than guessed from the output.
Nothing leaves your browser
- Entropy
- 129.8 bits
- Pool size
- 90
- Exhaustive search
- 3.9 × 10^19 years at 1 trillion guesses/sec
Entropy describes the draw, not the string: this Tool reports it only for secrets it generated. The estimate is exhaustive-search time; the average is half that.
Frequently asked questions
How is the entropy figure computed?
For a password it is Length × log₂(pool size): 20 characters from the full 90-character pool is 20 × 6.49 ≈ 129.8 bits, and excluding ambiguous characters shrinks the pool to 75 and the figure to ≈ 124.6 bits. For a passphrase it is Word count × log₂(7776), about 12.9 bits per word from the EFF list. The number describes the random draw, not the string it produced, which is why it is shown before you generate anything.
Why can a short generated password contain no digit or symbol?
Every character is drawn independently and uniformly from the whole pool, with no "guarantee one of each" placement, so the reported entropy is exactly Length × log₂(pool) rather than an overstatement. A missing class is just one outcome of a fair draw: with all four sets on, the chance a 16-character password has no digit is (80/90)¹⁶ ≈ 18%. Generate again, or raise the Length, if you need one.
What attacker does the search estimate assume?
It divides 2^entropy by an assumed 1 trillion (10¹²) guesses per second — a stated assumption about an offline attacker with commodity hardware against a fast hash, not a measurement of any real system. It is also the time to try every possibility; the average guess lands at half that.
Where does the passphrase word list come from?
The 7776-word EFF large wordlist ("EFF's New Wordlists for Random Passphrases"), © Electronic Frontier Foundation and licensed CC BY 3.0. It is vendored verbatim so the list size — and therefore the per-word entropy — is pinned.