Intro Bitting Photo Align Get Code

In the USA, almost all cheap residential door locks use one of two types of key: SC1, originally developed by Schlage, or KW1, originally developed by Kwikset. The key is uniquely identified by a five-digit code, where each digit represents the depth of the cut in the key that actuates a specific pin or wafer in the lock. There are also six-cut variants, SC4 and KW10. Most any locksmith can cut a key from this code, as can vendors from flea markets, eBay, craigslist, etc.

Head shape may vary. Keyway shape is what matters, but it's harder to judge. Click or tap image to enlarge.

This tool can determine that code from a photograph of the key. A couple startups offer apps that do something similar under the hood; but perhaps you'd rather use a local locksmith than wait for a key by mail, or perhaps your photo of the key doesn't meet their standards, or perhaps you just want to understand how it works yourself.


The bitting of a key is the geometric pattern of cuts that represents a particular code. Choose a predefined bitting, or enter a custom bitting.


The spacings from the shoulder of the key to the center of each cut are:

inches, comma-separated list, in same order as code (usually bow to tip)

The maximum width of the key (before it's cut) is:

For each code, the key width at bottom of cut is:

inches, comma-separated list, first width is code 0, then 1, then ...


In an ideal photo:

  • The key fills a lot of the frame.
  • The background is uniform, with high contrast against the key.
  • The lighting is bright, soft, and uniform.
  • The key lies within a few degrees of flat in the plane of the image.

Get PhotoUse Sample

You can still get the code from pretty bad photos; but aligning the outline will be harder, and you may have to judge the edges of each cut manually instead of automatically.


Zoom: In  Out  Fit    Mirror   Reset

The code for your key is:

If the detected edges of the cuts look wrong, then click or tap the bottom of a cut in the previous tab to place it manually.