How Long Does It Take to Crack a ZIP Password?
Updated July 2026 • 5 min read
"How long would it take to crack my ZIP password?" has a real, measurable answer, and it depends almost entirely on two things: which encryption scheme protects the archive, and how strong the password is. This guide shares the actual numbers from measured testing on real hardware, not marketing guesses, so you can understand exactly why some ZIP passwords fall in seconds and others would take longer than the age of the universe.
What these numbers mean, and do not mean
These figures come from real, measured benchmarks on GPU hardware, testing how many password guesses per second each ZIP encryption scheme allows. They tell you how fast an attack can run, not that any specific archive will be cracked. A weak, human-chosen password falls quickly on either scheme. A strong, long, random password is not recoverable by any free tool, no matter how fast the underlying attack runs, because the number of possibilities to check is simply too large.
ZipCrypto: seconds, not hours
Legacy ZipCrypto is the original ZIP password scheme, and by modern standards it offers almost no resistance to a dedicated attack. Measured testing on a single consumer GPU recorded a throughput of roughly 8.1 billion ZipCrypto password guesses per second. At that speed, an entire common-password wordlist runs in seconds, and any dictionary word, name, date, or short human-chosen password is found essentially immediately.
To put that number in perspective, a rented cloud GPU running the same kind of attack costs a fraction of a dollar for a full, generous attempt, well under a dollar for a run that covers billions upon billions of candidate passwords. Cracking a weak ZipCrypto password is, in practical terms, instant and essentially free for whoever is running the attack.
There is also a second, entirely different path that applies only to ZipCrypto: a known-plaintext attack (using a tool called bkcrack) that recovers the archive's internal keys directly from roughly a dozen known bytes of any file inside it, completely independent of how strong the password is. Predictable file types make this more available than it sounds. Between the raw guessing speed and this password-independent path, legacy ZipCrypto offers very little real protection against a determined attacker today.
WinZip AES: faster to attack than you might expect
WinZip AES uses genuine AES encryption, and it is far stronger than ZipCrypto overall. But measured testing turned up a real surprise: on the same hardware, WinZip AES can be attacked at roughly 27.4 million password guesses per second, which works out to around fifty times faster than an equivalent attack against a modern AES-256-protected PDF, and roughly four hundred times faster than password-protected Office 2013 documents.
The reason is specific and measurable: WinZip AES derives its encryption key using only 1,000 PBKDF2 hashing iterations, compared to the far more deliberately expensive key-derivation processes used by PDF and Office formats. Fewer iterations means each password guess is cheaper to test, so the attack runs faster even though the underlying AES cipher itself is just as strong.
At that speed, a full, budgeted attack attempt still costs only a few tens of cents on a rented cloud GPU, and a weak, human-chosen password typically falls within the earliest passes of a dictionary attack, seconds to minutes rather than hours. In other words: a modern, AES-encrypted ZIP with a weak password is, somewhat counterintuitively, more exposed than the equivalent PDF or Office document, purely because of how few rounds its key derivation uses.
Why a strong password still resists both
None of this means every ZIP password can be cracked quickly, and it is important to be precise about the boundary. In the same round of testing, random, twelve-character passwords on all three schemes, ZipCrypto, WinZip AES-128, and WinZip AES-256, were not cracked, even after exhausting a full, extended attack chain covering dictionaries, common password-mangling rules, and bounded brute-force search.
The reason is simple arithmetic. A truly random twelve-character password drawn from a reasonably large character set has so many possible combinations that even at tens of millions, or billions, of guesses per second, exhausting them all takes far longer than is realistic, in time or in money. Speed helps an attacker only up to a point; past that point, the size of the password space is what actually protects you.
This is why the honest recommendation is always about the password, not the encryption scheme. A long, randomly generated password protects you well on either ZipCrypto or WinZip AES. A short, memorable one offers very little protection on either, and essentially none at all on ZipCrypto.
What this means if you are trying to recover a password
If you have forgotten your own ZIP's password and are wondering whether recovery is realistic, these numbers translate directly into odds. If the archive is legacy ZipCrypto and the password was ever a real word, name, or short human-chosen string, it is very likely recoverable, and quickly. If it is WinZip AES with a similarly weak, human-chosen password, it is also realistically recoverable, just requiring a somewhat heavier attempt than a browser can run alone. If either scheme protects a genuinely long, random password, expect it not to be recoverable by any free tool.
Our own weak-password recovery attempt, built into zippasswordremover.com, runs a bounded version of exactly this kind of dictionary attack, entirely in your browser, for the easy cases described above. For the practical steps, see our guide to recovering a forgotten ZIP password, and for the full scheme-by-scheme comparison, see ZipCrypto vs AES recoverability.
How to reason about your own ZIP's crack-time
A quick way to size up your own situation using the numbers above:
- Identify the encryption scheme. Check the archive in a tool like 7-Zip to see whether it reports legacy ZipCrypto or WinZip AES-256.
- Estimate the password type. Be honest with yourself about whether the password was a real word or short phrase, or a genuinely long, random string.
- Weigh the two together. A weak password on either scheme is realistically crackable, quickly on ZipCrypto and quickly enough on WinZip AES. A strong, random password resists both.
- Act on the honest outcome. If your case looks recoverable, try the free weak-password attempt at zippasswordremover.com. If it looks like a strong random password, focus on finding it rather than attacking the file.
See if your ZIP password is in the recoverable range
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Frequently asked questions
How fast can a ZipCrypto password actually be cracked?
Measured testing recorded roughly 8.1 billion ZipCrypto password guesses per second on a single consumer GPU. A common or dictionary-based password typically falls within seconds.
Is WinZip AES really faster to crack than an encrypted PDF?
Yes, in measured testing WinZip AES was attacked at around fifty times the speed of an equivalent PDF AES-256 attack, because WinZip AES uses only 1,000 key-derivation rounds compared to PDF's far more expensive process. This still only meaningfully affects weak, human-chosen passwords.
Does a fast attack mean my ZIP password is unsafe?
Only if the password itself is weak. A genuinely random, sufficiently long password resists both ZipCrypto and WinZip AES attacks regardless of guessing speed, because the number of possibilities is too large to exhaust.
What is a known-plaintext attack, and does it apply here?
It is a technique, using a tool called bkcrack, that can recover a legacy ZipCrypto archive's internal keys from a small amount of known unencrypted content inside it, independent of password strength. It applies only to ZipCrypto, not to WinZip AES.
How long would it take to crack a strong, random ZIP password?
Far longer than is realistic in time or money, on either encryption scheme. In testing, random twelve-character passwords were not cracked even after an extended attack chain, which is why a long, random password remains the best real protection.