How to Open a Master Combination Lock

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Knowing how to open a Master Lock with its combination is seemingly useless if you're unable to remember the numbers in order. But all hope may not be lost, especially if you're dealing with an older padlock. In some cases, that old Master Lock padlock combination is recoverable, but you must have the lock's serial number.


Older models of Master combination locks carried the serial number on the body of the lock, but the company no longer prints the serial number on its retail locks. If you do have the serial number, you can get the combination from Master Lock, provided you can meet these two conditions:

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  1. You must be the rightful owner of the lock.
  2. The lock must not be attached to anything, such as a locker, bicycle, or storage box.


Operating a Master Combination Lock

A standard Master Lock combination lock has a combination with three numbers. You must stop on all of the numbers precisely in the correct order to open the lock. For example, if the combination is 2-25-15, you stop on the numbers in that order.

Here are the steps for opening a Master Lock combination lock:

  1. Turn the dial to the right at least three times.
  2. Stop on the first number in the combination. Using the example above, you'd stop on the line representing the number 2.
  3. Turn the dial to the left a full rotation so you go past the first number (in this case, 2) and stop on the second number in the combination. In this example, you'd stop on 25 after you do a full rotation.
  4. Turn the dial to the right again, stopping on the final number the first time you come to it. Using the above combination, you'd stop on 15.
  5. Pull the shackle away from the main part of the lock to open it. Once unlocked, the shackle rotates so you can easily put it through something to secure it.
  6. Push the shackle back into the lock when you want to relock it. Turn the dial a few times. Pull down on the lock to make sure it's secure.

How to Open a Master Lock With a Serial Number

Master Lock can give you the combination to a lock only if you have the serial number. The company will not give you a combination without the serial number or if the lock is secured to something. There are two options for obtaining the combination:


Take the Lock to a Retailer

Take the lock to a local hardware store, home center, or distributor that sells Master locks. The retailer can use the serial number and contact Master Lock to obtain the combination. The retailer may charge a fee for this service; Master Lock does not charge a fee.


Submit a Lost Combination Form to Master Lock

Your other option is to bypass the retailer or distributor and go straight to the Master Lock source with a lost combination form.

  1. Find your lock's serial number on the back of the lock body or on the lock's original packaging.
  2. Print out Master Lock's lost combination PDF form.
  3. Fill out the form and sign it before a notary public to have it notarized.
  4. Mail the notarized form to Master Lock at the address below. Master Lock will send your combination in about four to six weeks.


Master Lock Warehouse
24 North Free Port Drive
Nogales, AZ 85621


How to Open a Master Lock Without a Serial Number

While the Master Lock company can't assist with finding your lock's combination without a serial number, there are a few alternatives you can try to get your lock open.


Crack the Code

Sometimes, unlocking a combination lock without knowing the combination is possible with some time and patience.

  1. Hold the lock with the dial facing you.
  2. Firmly pull up on the lock's shackle to apply pressure.
  3. Turn the dial clockwise until you feel a subtle catch.
  4. When you feel the lock catch, note the number and add five. Write down the result.
  5. Turn the dial counterclockwise for one full rotation.
  6. Continue turning in the same direction until you feel resistance. The resistance indicates the second digit in the combination. Write it down.
  7. Turn the dial clockwise again while still applying pressure to the shackle. When you reach the final digit, the lock will open.


Consult a Locksmith

While picking your combination lock sounds easy enough, the task requires skill and patience. In most cases, taking your lock to a locksmith is the better solution. However, you will have to pay for this service.

Try Using Shims

In some cases, you can insert a small piece of metal or a store-bought padlock shim into the left side of the shackle connection point and manipulate the locking mechanism to open the lock. This method generally works only on older padlocks, and damaging the internal workings of the lock is a real possibility.


How to Change the Combination on a Master Lock

To change a Master Lock resettable (Set-Your-Own) combination, you'll need to have the old combination. The company cannot give you the combination because you created it, and the company has no record of it. Follow these steps to change the 3-digit combination lock.



  1. Open the lock with the old combination. (The combination for new numerical locks is all zeros.)
  2. Visit the Master Lock's support page: Reset & Retrieve Lost Combinations to identify your lock model.
  3. Follow the instructions for your model to reset your lock, or download the appropriate PDF if specified.

How to Open Up a Master Lock Box

Opening up a Master Lock box depends on your box type.


Push-Button Lock Box

  1. Depress the button labeled CLEAR.
  2. Press the number keys using the combination digits in order.
  3. Press the OPEN button and pull the compartment door open.

Combination Dial Lock Box

  1. Open the shutter door.
  2. Turn the dials to match the lock's combination.
  3. Push down on the release button while pulling the compartment door open.


What do you do when your Master Lock won't open?

There are several reasons your Master Lock might not open. Rust, freezing temperatures, or a damaged lock are all common culprits when a lock is stuck. Use lubrication to free a stuck dial. Wait for warmer temperatures or otherwise thaw a frozen lock. If you suspect you have a broken combination, take it to a locksmith or retailer to determine if it's salvageable.

Where is the reset lever on a Master Lock?

Resetting or changing the combination on a dial-activated Master Lock box involves using a reset lever. You'll find the lever inside the lock box's key-holding compartment on the unit's door. Look for a small, cylindrical metal lever on the right side of the inside of the door's locking mechanism.

How do you reset a Master Lock door lock?

Resetting or rekeying Master door locks requires using the old key, the one you intend to use to operate the lock, and a key-change tool.

  1. Insert the old key into the lock and twist it clockwise 90 degrees.
  2. Fully insert the key-change tool into the access hole.
  3. Remove the old key and replace it with the new one.
  4. Remove the tool and return the key to its original position.



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