SC1 Key Decoder Card for Schlage Keys

This is a printable decoder card for the Schlage SC1 keyway, a widely used residential key profile in North America. With this tool, you can quickly and accurately read the bitting (cut depths) of any SC1—ideal for locksmithing, key management, or hobbyist curiosity.

About the SC1 Keyway

The Schlage SC1 keyway (also known as the Classic “C” keyway) has been a cornerstone of residential and light commercial locking systems in the United States for decades. Manufactured by Schlage, the SC1 became widely adopted due to its tighter manufacturing tolerances and broader depth range compared to many competing residential keyways.

The SC1 is typically configured as a 5-pin tumbler system, though many locks also support 6-pin versions. It uses ten standardized cut depths (0–9), allowing for a greater number of key combinations and expanded master keying capability.

Today, SC1 remains one of the most prevalent key profiles in North America, commonly found in homes, apartments, small businesses, and many smart lock platforms. Its durability and flexibility have made it a long-standing industry standard in residential security.

What This Tool Does

This decoder card helps you determine the cut depth of each pin position on a SC1 key by aligning it with engraved reference lines. It’s a simple, manual tool—no electronics, no moving parts.

This is useful for:

• Locksmiths and technicians working in the field
• Homeowners documenting their own key systems
• Hobbyists learning about locks and bitting patterns
• Inventorying or replacing lost keys without lock disassembly

How to Use It

Insert your SC1 key into the slot, cutouts facing down, resting the shoulder against the stop.
Align each cut with the reference marks to determine its depth.
Read the bitting from bow to tip (e.g., 3-1-5-4-2).
Use that bitting to cut or record a key, if you have the legal right to do so.

The markings follow the standard Kwikset cut depth increments. You’ll get a quick, approximate read that’s accurate enough for field work, home use, or education.

Legal & Ethical Reminder

This tool is for legal, ethical use only. Do not decode or duplicate keys you do not own or have permission to handle. Unauthorized use of key decoding tools may be illegal in your area.