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:
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.
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.