How Many Possible Combinations for a 3-Digit Lock? | 1,000 Made Simple

A standard 3-digit lock with wheels labeled 0 through 9 has exactly 1,000 possible combinations, from 000 to 999.

But the real answer depends on one thing: whether the lock allows repeated digits. Most standard locks do, which makes the math simple, but variations like no-repetition rules or locks using digits 1 through 9 change the count. Here is what each scenario actually produces and how to verify your lock’s type.

The Standard 3-Digit Lock Calculation

A three-wheel lock works like a permutation machine. Each wheel offers 10 positions (0 through 9), and the order of the digits matters. The math is straightforward: 10 × 10 × 10 = 1,000. That is the total number of unique sequences any standard 3-dial lock can produce. A sequence like 123 is different from 321, and 000 is a valid combination.

When Digits Cannot Repeat (No Repetition Rule)

Some locks, especially higher-security models, prohibit repeated digits. Under that rule, the same digit cannot appear more than once in a combination (121 would be invalid). The count drops to 720, calculated as a permutation of 10 items taken 3 at a time: P(10, 3) = 10 ÷ 7! = 720. The first wheel has 10 options, the second has 9, and the third has 8. You lose about 28% of the total combinations — and the security level drops accordingly.

When Order Does Not Matter (Unique Combinations)

This is extremely rare on physical padlocks, because most rely on the order of the wheels to create security. Only certain low-end or toy-style locks use this unordered scheme. The real-world takeaway: if your lock has rotating wheels, it uses permutations, not combinations — so use the 1,000 count.

Other Common Variations

Some locks exclude the digit zero entirely, using only 1 through 9 on each wheel. That produces 9 × 9 × 9 = 729 combinations. The correct answer always depends on the lock’s mechanics, not on a guess.

Common Mistakes People Make

The most frequent error is confusing permutations with combinations. In everyday language, “combination” often means order doesn’t matter, but lock security relies on order. That is why the correct answer is 1,000, not 120. Another common mistake is assuming zero is excluded — many people miscalculate as 729 instead of 1,000. And a 4-digit lock has 10,000 combinations, not 1,000. Knowing your lock’s repetition policy is the single most important check; standard locks allow repeats, but high-security models may not.

How to Verify Your Lock’s Actual Type

Not every three-wheel lock works the same way. If you are shopping for a new lock or checking an existing one, the fastest way to confirm its behavior is to test a repeating combination like 111. If the lock opens, it allows repetition. If it doesn’t, your lock prohibits repeats and has 720 possible combinations. For anyone ready to pick a reliable model, our tested roundup of the best 3-digit padlocks covers options that fit each scenario.

Here are the most common lock configurations and their exact combination counts:

Security Reality: 1,000 Combinations Is Low

With only 1,000 possibilities, a brute-force attack can test every combination in minutes. For real security needs — luggage containing valuables, gym bags, or lockers with sensitive items — a 3-digit lock is a convenience device, not a security barrier.

Here is how the most common lock types compare for practical security:

Quick Reference: Finding the Right Count for Your Lock

Grab your lock and check the wheels. If they show digits 0–9, you are looking at the standard 1,000-combination lock. If the wheels only go from 1 to 9, the count is 729. If you are unsure about the repetition rule, test 111. If that opens, repetition is allowed. If it doesn’t, your lock uses the 720-combination scheme. For most people, a standard three-wheel padlock with 0–9 digits and repetition allowed is what they own — and the answer is 1,000.