Random PIN Generator

How the Random PIN Generator works

Random PIN generator: why 1234 is the problem

A four-digit PIN has 10,000 possibilities, which sounds small and is, but the real weakness is not the length. It is that people do not choose from all 10,000. An analysis of 3.4 million leaked four-digit PINs found that 1234 alone accounted for almost 11% of them, the top twenty covered more than a quarter, and years of birth from 1950 to 2000 filled most of the rest of the top few hundred. An attacker with three guesses before lockout who tries 1234, 1111 and 0000 gets into nearly one in five accounts. A random PIN moves you out of that group entirely.

What the generator refuses to produce

Each digit is drawn independently from 0 to 9, so every code is equally likely to start with. Two families of results are then thrown away and redrawn: codes made of a single repeated digit, and straight ascending or descending runs including 0123 and 9876. Those are the codes at the top of every guess list, and rejecting them costs almost nothing in the total space — 24 of 10,000 four-digit codes — while removing the one case where a random draw would hand you a code an attacker tries in the first minute.

Four, six or eight digits

Four digits is what most bank cards and older phones allow, and it relies entirely on the lockout: three wrong attempts and the card is swallowed, ten and the phone wipes. Under that rule a random four-digit PIN is fine, because the attacker's odds are three in ten thousand. Six digits is the current phone default and the right choice wherever it is offered, since 1,000,000 codes makes even a patient attacker with a slow brute-force rig wait days. Eight is for systems that let you choose and where the code protects something valuable. None of them is a substitute for a password where a password is allowed: a PIN is only safe when something limits the guesses.

Where a PIN is the wrong tool

A PIN protects a device or card that an attacker must physically hold and that locks after a few tries. It does not protect an online account, where guesses are free and fast, and it should never be the same code across your phone, bank card and door. Use a different random code for each, and if a service offers a longer password or a passkey instead, take it.

Generated locally, never sent

The digits come from crypto.getRandomValues in your browser. No request is made when you generate, nothing is logged, and the codes exist only on this page until you copy them. Reload and they are gone.

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