Ask ten websites how long your password must be and most still say eight characters. That number is a fossil. It dates from an era when attackers guessed passwords by hand or with modest CPUs, and it has survived in password policies purely through inertia. Meanwhile the hardware doing the guessing improved by orders of magnitude: a single consumer GPU can now test billions of candidate passwords per second against a weakly hashed database. Against that reality, the length question has a data-driven answer, and it isn't eight. For anything you care about, the practical floor is 16 random characters - And the reasoning behind that number is worth ten minutes of your time, because it inoculates you against most bad password advice.
Why length beats everything else
Password strength is measured in entropy - The number of possibilities an attacker must search, expressed in bits. The formula is simple: length × log₂(pool size). The pool is how many different characters each position could hold; the length is how many positions there are.
That formula hides an asymmetry that most people miss. Growing the pool helps logarithmically: going from lowercase letters (26) to the full printable set (95) roughly buys you 1.9 extra bits per character. Growing the length helps linearly in bits, which means exponentially in guesses: each extra full-pool character multiplies the search space by 95. Adding two characters to a password does more than adding every symbol on your keyboard to its pool. The deep math is laid out in our guide to password entropy, but the headline is enough: length is the lever that matters.
When in doubt, don't make it fancier - Make it longer. Two extra random characters beat every symbol substitution you've ever used.
What the crack-time data shows
Hive Systems publishes a widely cited annual table of how long a rig of modern GPUs needs to exhaust passwords of a given length, assuming the attacker has stolen a database of hashed passwords and is grinding through it offline. The exact figures shift with each GPU generation - Which is precisely the point. A length that was "years" in 2020 became "days" once newer hardware shipped. Here is the shape of the current picture for random passwords using upper- and lowercase letters, numbers, and symbols, against a fast hash:
| Length (random, full character set) | Approximate offline crack time |
|---|---|
| 8 characters | Minutes to hours |
| 10 characters | Weeks to months |
| 12 characters | Decades |
| 14 characters | Hundreds of thousands of years |
| 16 characters | Millions of years and up |
| 20 characters | Longer than the age of the universe |
Two things about this table matter more than the numbers themselves. First, notice how violently the times escalate - That's the exponential at work. Second, notice the assumption in the left column: random. The table describes passwords where every character was an independent random draw. Manchester2019!! is 16 characters and would fall in seconds, because attackers don't search the random space - They search words, names, dates, and predictable decoration first.
Why 8 characters died
The eight-character standard traces back decades, to systems that literally could not store more, and it hardened into policy during the 1990s and 2000s. Three developments killed it:
- GPU cracking. Password-cracking software like hashcat turned gaming graphics cards into guessing engines. Against MD5 or SHA-1 - Still disturbingly common in breached databases - A single card tests tens of billions of guesses per second. The full 8-character space is about 95⁸ ≈ 6.6 quadrillion possibilities: a weekend project for one machine, minutes for a rig.
- Breach-trained wordlists. Billions of real passwords have leaked over the past fifteen years. Crackers feed them, plus mangling rules, into their tools, so human-chosen 8-character passwords rarely require brute force at all. Our breakdown of how hackers crack passwords walks through the full toolkit.
- Offline attacks became the norm. Rate limits protect a login page, where an attacker gets a few guesses per second. But when a site's database leaks, the attacker guesses on their own hardware with no limits. You don't get to choose which scenario you'll face, so you have to dress for the worst one.
NIST's current guidance in SP 800-63B reflects this shift: it sets a minimum of eight characters only as an absolute floor, explicitly encourages much longer passwords, and tells services to accept passwords of at least 64 characters so users can employ passphrases.
The honest recommendation: 16 as the floor
For a password stored in a password manager - Which should be nearly all of them - There is no cost to length. You'll never type it. Generate 16 to 20 random characters with a password generator and you've bought yourself roughly 105 to 131 bits of entropy, comfortably beyond any conceivable offline attack, even against a fast hash, even accounting for a decade of hardware improvement.
Why not stop at 12, which the table says survives for decades? Margin. You don't know how a site hashes your password, you don't know how long the stolen database will circulate, and you don't know what hardware exists in ten years. Twelve random characters is probably fine today; sixteen is fine even if you're wrong about all three unknowns. Since the price of the extra margin is zero, take it.
For the handful of passwords you must actually type and remember - Your password manager's master password, your computer login - Random character soup at length 16 is miserable. That's the niche for long passphrases: a string of random common words. Six words drawn from a proper wordlist give you roughly 77 bits while remaining genuinely memorable, and a passphrase generator will do the drawing honestly. The catch, covered in what is a passphrase, is that the words must be randomly chosen - A lyric, a quote, or a sentence you thought up has a fraction of the entropy its length suggests.
When long passwords still fail
Length protects you against guessing. It does nothing against the other ways passwords get stolen:
- Reuse. A 30-character masterpiece reused on five sites is only as safe as the worst of the five. Credential-stuffing attacks replay leaked passwords everywhere.
- Phishing. You'll type a long password into a fake login page just as happily as a short one.
- Malware and interception. A keylogger captures 20 characters as easily as 8.
- Bad recovery paths. If "forgot password" only requires your pet's name, your password length is irrelevant.
That's why length is necessary but not sufficient. Pair it with uniqueness per site and two-factor authentication, and check what a strength estimator actually says about your candidates with a password strength checker - A good one models dictionary patterns rather than just counting characters, and it runs locally in your browser.
How to upgrade without pain
Nobody should hand-migrate 200 accounts in one sitting. A sane rollout: first, fix the master password and your primary email account today - Those two protect everything else. Second, let your password manager flag short and reused passwords, and replace them opportunistically whenever you log in to a flagged site. Third, set your generator's default length to 20 so every new account starts strong. Within a couple of months the problem solves itself, and the strong defaults do the remembering for you.
FAQ
Is a 12-character password still safe in 2026?
A truly random 12-character password (~79 bits) remains out of reach for offline cracking against any hash, and will for years. The problem is the qualifier: most human-made 12-character passwords are a word plus decoration, worth 30-something bits. If a generator made it, 12 is acceptable; 16 costs you nothing extra and adds a decade-proof margin.
Is a longer password always stronger?
Only if the added characters are unpredictable. passwordpasswordpassword is 24 characters and would be found almost instantly, because cracking tools try repeated and concatenated dictionary words early. Length multiplies strength only when each character (or each word, in a passphrase) is an independent random choice.
What's the ideal length for a master password?
Aim for the equivalent of 90–100+ bits: a passphrase of six to eight randomly generated words, or 16–20 random characters if you can genuinely memorize them. A master password protects an offline-attackable vault, so it deserves more margin than ordinary logins - And it's the one password that must live only in your head.
Do maximum length limits mean a site is insecure?
A cap around 64 or 128 characters is reasonable engineering and NIST-sanctioned. A cap of 12 or 16 - Or a site that forbids pasting - Is a yellow flag suggesting dated practices. A very low cap (8–10) sometimes indicates the password is stored or processed in a legacy system; use your longest allowed random password there and enable 2FA.
Does adding symbols let me use a shorter password?
Barely. Moving from letters-and-digits to the full symbol set adds about 0.6 bits per character, while each additional character adds roughly 6. If a site's rules force symbols, include them, but never trade length away to get them. Four extra characters beat every symbol on the keyboard.