What Type of House Key Do I Have?

House keys seem simple until you actually need to replace one. Then you find out not every house key is the same.

The good news is most homes in the U.S. use one of a small handful of common keyways. At Custom Keys, we make house keys for two of the most common ones: KW1 and SC1. 

Those two keyways cover a lot of standard residential locks, but they don’t cover every lock. Before you buy a new key, get one copied, or head to a locksmith, you need to know which keyway you’re working with.

Here’s how to check.

1. Check for a Stamp

Look at both sides of your key, especially near the top where you hold it. Some manufacturers stamp the key with a code like KW1 or SC1.

Stamp on your key? You're done before you even started. Match your new key blank to that same keyway and shop CustomKeys.com.

No stamp? Don't sweat it. Some keys just don't have one. Let's move on to the next step and check the shape and grooves.

2. Look at the Shape of the Key

Lay your key flat on a table and look at the top part of the key.

A KW1 key usually has a rounded, five-sided shape. It looks a bit like a soft pentagon, with smoother sides and rounded corners.

An SC1 key usually has a more angular shape. It often looks closer to a diamond or shield, with more noticeable points and notches.

That said, the head shape is only part of the story. Key manufacturers don’t always make every key head exactly the same, so the shape can point you in the right direction, but it shouldn’t be your only clue.

3. Dont Forget the Grooves

This is where a lot of people get tripped up. The cuts along the edge of your key are not the only thing that matters. The grooves running along the blade of the key matter too. Those grooves are what allow the key to slide into the right lock cylinder in the first place.

Make sure you check both sides of the key. One side might look close, while the other side tells a completely different story.

A KW1 key and an SC1 key can have a similar size and general shape, but the grooves are different. If those grooves don't match the lock cylinder the key simply won't go in, and a key that doesn't go in isn't unlocking a thing.

Want a Visual?

If you’re still not sure which house key you have, check out our quick video guide for a closer look at the difference between common keyways.

What the Right Keyway Matters

KW1 and SC1 keys are both common, but they are made for different lock cylinders. You can’t swap one for the other and expect it to work.

If the keyway doesn’t match, the key may not slide into the lock at all. And if it doesn’t fit the lock, it’s not going to open the door.

So start with the stamp. Then check the shape. Then look at the grooves on both sides. That should give you a much better idea of whether you have a KW1 or SC1 house key.

See 66 or 68 stamped on your key instead? Same keyways, just a different stamp. Check out our 66/68 key guide to see what that means before you order.