How to Crack a Masterlock Padlock.





Introduction: How to Crack a Masterlock Padlock.

This little instructable will demonstrate how to narrow down the possible combinations for your lock from over 60,000 to 80. This is good for if you lose "your" combination.

Step 1: Knowing Thy Lock.

Before you find your numbers, you must know a few things about your lock.

First of all, there is a dial, a body, and a clasp (The U shaped thing on the top that comes out when unlocked).

When you open your lock you would normally spin the dial right a few times to reset, then go to your first number. Then, you would turn left, passing your first number once, then stopping on your second number. Finally, you would turn right again to your third, and final number and pull on clasp.

Okay, now you know thy lock.

Step 2: Finding Your Third Number

First, you must find your 3rd number of 3. To do this, turn right a few times to reset, then go to 0 on the dial. pull hard on the clasp and turn left a little until you notice your dial only turns within a little space. Now, you will need to use your brain cells to figure out the number in the middle. For instance, if the dial were stuck between 3 and 4, the number would be 3.5. Once you have your middle number written down, release the clasp, and turn left one number and pull again and turn more until you are stuck in another groove. Write down the number in the middle of the space. Repeat this process until you get 12 numbers. Not 8; 12. Okay? Your list might look like this:


So what you do, is take your pencil and cross out all the numbers with decimals (.5, .25, .75)
now you should have 5 numbers. If not, you didn't use enough brain cells to get the right middle number. Try again. But if you do have 5, you will notice 4 of the 5 end in the same number. Cross these out to. That should leave one number. In the case of the list above, that number would be 19.
That final-left number, is your third number.

Step 3: Finding Your First Number.

Okay. Now that you have you third number, it's time to get your first. Take your third number and divide it by four. Take the remainder. In our example our 3rd is 19 so we divide by 4 and keep the remainder. In this case, it would be 3. Hard? No. Now take your remainder ( Either 0,1,2, or 3) and write it down. now add 4. now write that down. Now add 4 to That new number. wright it down. Keep doing this pattern until you have 10 numbers down. Now stop. These are all the possible first numbers. Hooray!

19/4 = 4 R3(remainder)
3 + 4 = 7
7 + 4 = 11

3,7,11,15,19,23,27,31,35, and 39

Step 4: Finding Your Second Number.

Mmmkay. Now think way back 5 minutes ago and try to remember that little remainder. If its a 0 or a 1, add 2 , if its a 2 or a 3 subtract two. Now add 4. Write down. Do that 9 more times. Good job. Now take away any numbers +/- 2 from your third number. Now you have all the possible numbers for your second number.

Remainder = 3
3 - 2 = 1
1,5,9,13,25,29,33, and 37

Step 5: Narrowing It Down Even More.

Okay. Now you should have 10 1st numbers, 10 2nd numbers, and 1 third number.
Now remove any 2nd numbers +/- 2 from your third. Wallah! you know have narrowed it down by 20 poss. combinations.

Step 6: Finding the Right One

Now take your numbers and make a table and try out all the diff combos and cross them off if they don't work, so you can remember.
P.S. This may not work on older models and ones with locks in back.(Haven't tried any of those yet)



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What if you know your third number from memory?
Would this have any effect on the lists for your possible first and second numbers?

I have a problem, I only have four whole numbers for the first few steps. (2.5, 6, 9.5, 12.5, 16, 19.5, 22.5, 26, 29.5, 32.5, 36, and 39.5) I have done and redone the process multiple times and have gotten the same result every time. How do I find my third combination number?

I know that my third # is 20 cuz the last five # were 6, 16, 20, 26, and 36. I got 10 1st #s 0,4,8,12,16,20,24,28,32, and 36. I got 10 2nd #s 2,6,10,14,18,22,26,30,34,and 38.
How do i make twenty combinations left. I dont get the next step.

1 reply

I assume you are referring to the step that says "remove any second numbers +/- 2 from third number"

it simply means...

Take your third number. In this case, it is 20.
+/- 2 from 20 is going to be any number from 18 to 22
Remove those from your list of 2nd numbers.
So, in your case, you are only removing 18 and 22 from your list.

I know that my third # is 20 cuz the last five # were 6, 16, 20, 26, and 36. I got 10 1st #s 0,4,8,12,16,20,24,28,32, and 36. I got 10 2nd #s 2,6,10,14,18,22,26,30,34,and 38.
How do i make twenty combinations left. I dont get the next step.

Does not work in my purple master lock. Middle number are all 1, 4, 7.5, 11, 14... so no number is left after crossing the "repeating ends".

While I was doing this I forgot to skip the 2nd numbers that are within +/- 2 of the 3rd. As it turned out, one of those is correct. Since you can get a lock where the 2nd number is within 2 of the 3rd, those shouldn't be taken out.

okay I have a master lock with 19 numbers. Will this still work??

well i bought a new one and it is not getting unlocked no matter what i tried and i know the combination

Wow! Actually worked. Got it in 5 minutes.

as long as we're sharing numbers her how about you're social security number, kidding don't share that online bad idea

Thanks for the warning, but this padlock isn't necessarily guarding anything valuable :p Hence why I felt safe enough to share the combo.

Seriously, thank you. I had watched videos and used that guys little formula and for w/e reason my resistant number wasn't that resistant, so it would have taken me forever, but yours worked perfectly.

Wow, worked like a charm. Thanks!


Totally worked!

It works!!! I was about ready to give up, I had already done over 70 combinations and then my lock opened! Great instructable!

I was able to do this in 10 minutes - but I knew the first number so it was a matter of trying the middle number. I got it in 2 tries.

Great instructions -thanks!

Didn't work for me... I've got 32 as the last number 1st number = 0,4,8,12,16,20,24,28,32,36 2nd number = 2,6,10,14,18,22,26,30,34,38 I go CW 3 times, then I stop in 1st number, then I go CCW passing 1 time infront of 1st number before I hit 2nd number, then I go directly to 32 (3rd number) = nothing I did it 3 times already... I'm sure about the numbers, I think is the way I'm spinning the dial. I need some insight???

This worked on a lock I bought in the late 80's. Remembered the correct sequence before I turned the dial on the last combination. Sometimes just setting up the sequences will trigger the memory - if it's a lock you opened a few times. Many years ago. Thanks for the Instructable!