Key System Expansion Calculator

Maximum key combinations from pin count and depths.

Pins per lock

Available depths

MACS

Current keys in system

Keys to add

Master key levels

Tab to move between fields

Effective key capacity

60,505

Theoretical combinations1,000,000

Current utilization (%)0.1%

After expansion (%)0.1%

Remaining capacity60,425

Years until full2,014.2

Cross-key risk (1-5)1

Expansion cost$840.00

Upgrade Recommended0

How to Use This Calculator

Enter the current number of keys and cylinders in the master key system.
Set the number of new openings and key holders to add.
Select the key blank series and master key hierarchy levels.
Review the additional keys and cylinders required and whether the current system has expansion capacity.
If the system is at capacity, plan a system re-key or upgrade to a higher-security interchangeable core system.

How the result changes with Pins per lock

Pins per lock: Number of pin positions in the cylinder (5, 6, or 7).
Available depths: Number of key cut depths (Schlage = 10, Kwikset = 7, Best = 8).
MACS: Maximum Adjacent Cut Specification for the keyway.
Current keys in system: Number of unique change keys currently issued in the system.
Keys to add: Number of new change keys you plan to add.
Master key levels: Number of mastering hierarchy levels (1 = simple, 4 = complex).

Effective key capacity: Usable change key capacity after MACS and master keying overhead.
Theoretical combinations: Raw bitting combinations before any constraints (depths^pins).
Current utilization (%): Percentage of system capacity currently in use.
After expansion (%): Utilization after adding the planned new keys.
Remaining capacity: Number of additional change keys available after expansion.
Years until full: Estimated years before system reaches capacity at current growth rate.
Cross-key risk (1-5): Risk of incidental cross-keying: 1 = Very low, 3 = Moderate, 5 = Critical.
Expansion cost: Estimated cost for adding new keys including any system redesign.

Identify Input Parameters
4 parameters
Pins per lock = 6, Available depths = 10, MACS = 4, Current keys in system = 50 = 6 input(s) provided
Calculate Effective key capacity
Effective key capacity
60505 = 60505
Calculate Theoretical combinations
Theoretical combinations
1000000 = 1000000
Calculate Current utilization
Current utilization = currentKeys / max(1, effectiveCapacity) * 100
0.1 = 0.1%