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Zeropingtools.online • Fast & Private
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Bootstrapping high-performance module...
Bootstrapping high-performance module...
Calculate bits of entropy and estimated brute-force time locally. No password leaves your browser.
Processed locally. Your password never leaves your browser.
Entropy
0 bits
Brute-Force Time
@ 1G guesses / sec
Entropy measures unpredictability. Higher bits mean the password is exponentially harder for algorithms to guess.
The Password Entropy Calculator moves beyond simple 'Weak/Strong' labels by calculating the exact mathematical effort required to crack a password. It provides a technical 'Bit-Score' that reflects the true diversity and length of your character set.
Entropy is measured in bits: it describes how many equally likely guesses an attacker would need on average. More bits mean exponentially more combinations. This tool estimates entropy from character classes and length using a simplified model—good for comparing candidates, not a formal cryptographic proof.
The crack-time label assumes a very fast offline attack (billions of guesses per second). Real attacks may be slower (rate limits, hashing cost) or faster (GPU farms, leaked password lists).
Long random passphrases from a word list often beat short complex passwords humans reuse. Pair a unique password per site with a password manager and enable multi-factor authentication where available—entropy alone does not stop phishing or database leaks.
Entropy is calculated using the formula: $E = L imes log_2(R)$, where $L$ is length and $R$ is the size of the character pool (charset). A password's strength is exponential—adding just one character to a 12-digit password can increase its resistance by billions of times.
A score of **60 bits** is considered a minimum for basic accounts, while **80-100+ bits** is the gold standard for critical infrastructure and financial master passwords.
No. Everything runs in your browser; the password stays in page memory and is cleared when you close or refresh the tab.
Sites use different rules and may not measure entropy. This meter rewards length and character diversity; some sites only check minimum length or complexity rules.
Not if the phrase is long and random enough (e.g. several words chosen independently). Short dictionary passwords and predictable substitutions remain easy to guess.
High entropy does not help if the exact password was leaked. Use unique passwords per account and check breach notifications from your browser or provider.
Aim for at least 80 bits for secondary accounts and 100+ bits for your primary email, bank, or password manager vault.
Yes. If a database is leaked, hackers will try to 'crack' the hashes offline. A high-entropy password ensures that even with massive GPU power, it would take years or centuries to reverse-engineer your plaintext.