Forgot Your Padlock Combination? How to Get Your Own Lock Open

Forgot the combination to your own padlock? Ask the maker first: Master Lock can look up the code of a padlock with a serial number on the back. If it’s a cheap 3- or 4-wheel lock you set yourself, nobody has a record of it, so you either work through the codes or cut it off.

Forgot your padlock combination? The short answer

Which way out depends on two things: who set the code, and whether there’s a serial number on the lock. A factory-set Master Lock dial padlock with a serial number can be looked up by the maker. A lock whose code you set yourself can’t, because the maker never knew it.¹ Here’s the order we’d go in.

Master Lock lost combination: the maker’s route

Master Lock is the only padlock maker we found that publishes a clear route for a forgotten combination, and the whole thing hangs on one detail: a serial number. Its support page is blunt about locks without one: “we don’t have a record of it.”² So before anything else, turn the lock over.

Find the serial number

Master Lock’s own guide to the markings shows where to look. A commercial dial padlock such as the 1502 carries a serial number and a date code stamped on the back (its example reads 505000 above 3409). A retail-packaged dial lock such as the 1500D may have both, or only a date code, depending on when it was made. A Set-Your-Own lock may have a date code, but Master Lock can’t retrieve its combination, because “Master Lock has no record of the combination.”¹

Don’t confuse the two numbers. A date code is a short mix of digits and sometimes a letter (3109M on the 1500D in the guide); it tells the factory when the lock was made, not what opens it. If you can’t tell which you’ve got, the guide gives Master Lock’s customer care number, 800-464-2088, with one condition: “Combinations cannot be released by phone.”¹

In the US: retailer or photo

Master Lock’s US support page offers two ways to recover the combination of a serial-numbered lock.²

1. Through a Master Lock distributor or retailer. Take the lock in yourself, not attached to anything. If you don’t bring the lock, or it’s still on something, they won’t release the combination. Master Lock doesn’t charge for this, though the retailer may.
2. By photo. Use the Contact Us form on masterlock.com and choose the Lost Combination option. The photo has to show the whole lock and its serial number, with the lock visibly not attached to anything; edited photos are rejected. Master Lock says it replies in 7 to 10 days.

The same page links a printable Lost Combination Form. It’s a sworn statement: you write your name and the serial number, attach a photocopy of the back of the padlock, sign it, and a notary public signs and dates it.³ It’s a lot of ceremony for a gym lock, and that’s rather the point: the combination goes to the person who can show they own the thing.

In the UK and Europe: by email

Master Lock Europe asks for the request by email to its after-sales team, with the model and serial numbers, and says to allow about 4 to 6 weeks. The rules are the same: no combinations for locks without a serial number, and none for a lock that’s attached to anything.⁴

What Master Lock won’t do

• Give a combination for a lock that is attached to anything, by any route.²
• Reset a Set-Your-Own or resettable lock without the current combination. Its answer, both in the US and in Europe, is that you’ll probably need a new lock.²⁴
• Read out a combination over the phone.¹

One small mercy: if you’ve lost the little reset tool that came with a resettable lock (and still know the code), Master Lock says it can send a replacement free of charge if you give it the model number or a photo of the lock.⁴

Other makers, and school locker locks

We looked for a published lost-combination route from other padlock makers and came back nearly empty-handed. The one exception we found is a feature of particular models rather than a service: a retailer’s listing for the ABUS 158KC/45 says a lost or forgotten code can be overridden, reset and identified with a master key, sold separately.⁵ If you own a different model, check its leaflet or ask the maker before you assume there’s a back door.

School locker locks are a different case. The padlock usually isn’t yours, so the combination isn’t yours to recover. Schools hold the records: Master Lock supplies combination charts to schools (now electronically, through a chart request form), and the keys for its keyed locker locks are reserved for the registered school or business.⁶ One California high school, for instance, issues its students a school Master Lock and says forgotten combinations can be retrieved from the attendance office, main office or campus supervision office.⁷ Go there. And since Master Lock won’t release a combination for a lock attached to anything, a padlock hanging on a locker door can’t be sorted out through the maker anyway.²

Recovering the code of your own 3- or 4-wheel padlock

I’ve done this myself, with the 4-digit padlock on my gym locker. So if you’re reading this in a changing room, no judgement here. Cheap number-wheel padlocks (luggage locks, cable locks, gym and bike locks) are the ones you’ll most often have set yourself, which means there’s nobody to ask. What’s left is patience.

Start with the codes you actually use. Most of us recycle a handful of numbers: an old PIN, a year, a door code, the last digits of a phone number. Try those first. Then think about when you set the lock: a code chosen on holiday or on the first day at a new gym often borrows something from that moment.

Then work through them in order. A wheel padlock has no memory and no lockout, so the honest method is to try every combination systematically: leave the first wheels where they are, run the last wheel from 0 to 9, move the wheel before it on by one, and repeat. The maths is short.

On average you’ll find the code about halfway through, so a 3-wheel luggage lock is an evening in front of the television. A 4-wheel lock is more of a weekend, and that’s the point where a cheap padlock stops being worth the time: cutting it off and buying a new one is the sensible answer, and there’s no shame in it.

The locksport rules we write by

Lock picking as a hobby, usually called locksport, has rules, and they’re the ones this page follows. The Open Organisation Of Lockpickers (TOOOL) asks its members never to pick or manipulate a lock that isn’t theirs unless the rightful owner has given explicit permission, and never to pass skills or tools to anyone they suspect would use them for crime.⁸ The intro talk at the DEF CON Lock Picking Village in 2015 opened with two rules: don’t pick locks you don’t own, and don’t pick locks you rely on, “even if it’s your front door lock”.⁹

That second rule is why this section stops where it does. Locksport talks explain that inside a number-wheel padlock each dial turns a wheel with a flat or a gate, and the shackle only releases when every gate lines up; on cheap designs hobbyists learn to see or feel that gate, which they call decoding.¹⁰ We’re keeping it at that level. For your own luggage lock, the 1,000 tries above get you there without a single tool.

Forgot the combination on a dial padlock

The classic school-style padlock with a spinning dial and three numbers is a different animal. Trying every combination by hand isn’t realistic, so the order is simple.

1. Look for a serial number on the back. If it’s a Master Lock with one, use the maker’s route above.¹
2. Check whether it was issued to you. A locker padlock from a school, gym or employer goes back to the office that issued it.
3. If it’s yours and there’s no record, cut it off. A cheap padlock usually costs less than a locksmith’s call-out, and a pair of bolt cutters from a neighbour or a hardware shop deals with most of them. A locksmith is the answer for a hardened shackle, or if you’d rather not do it yourself.

You may have read that dial padlocks can be decoded. They can, and the work is published in locksport and security circles: in 2015, for example, the security researcher Samy Kamkar drew wide attention with videos showing a Master Lock combination padlock opened in under eight tries.¹¹ We don’t reproduce any of it here. It’s a lesson in why a cheap padlock is a deterrent, not a vault, rather than a fix for a forgotten code.

Next time: make the code hard to lose

The cheapest fix is the one you do the day you buy the lock. Master Lock runs a service called Store Your Combo: you register an account and save each lock’s model number and combination (or key code), so you can look it up later. If you lose access to the email you signed up with, the serial number lets you set up a new account.¹² Master Lock Europe describes its version, at masterlockvault.com, as a free service.⁴

If you’d rather not put it online, a note in your password manager, or on a card at home (not in the bag the lock is guarding), does the same job. For the gym or a suitcase, a resettable padlock lets you pick a code you’ll actually remember; our guide to how to open and reset a combination lock covers how the reset works on the common types. Test the new code with the lock open before you rely on it.

A bit of history

The notched wheel in your luggage lock has a long pedigree. In 1843 Linus Yale and Charles Wilson patented a combination safety-lock for doors and trunks, in which pairs of notched disks held the bolt until the notches lined up.¹³ Changing the combination easily came later: in 1888 Thomas S. Spivey of Cincinnati patented, for the Victor Safe and Lock Company, a permutation lock with a combination changer, an early answer to the job your padlock’s reset lever does today.¹⁴

Opening a lock with its owner’s blessing is old too. Bramah’s shop in Piccadilly kept a padlock in the window offering 200 guineas to whoever could pick it, and in 1851 the American A. C. Hobbs took up the offer and won, a story we tell in full in the Great Lock Controversy of 1851.¹⁵ For the bigger picture, see our history of lock mechanisms.

Frequently asked questions