Master key planner

Enter the top master key and how many change keys you need. You get the change key bittings, the pins for every lock and a key schedule to print, with the MACS rule checked on every key.

Your system

Example values: change them to yours

System name (for the schedule)

Lock

5 positions, depths 0 to 9 for change keys, MACS 7.

Top master key (TMK) cuts

First cut nearest the bow. Cuts near the middle of the range leave the most change keys.

Change keys needed

Progression

Two-step (Schlage has no #1 master pin)

What this master key allows

Change keys possible

634

Skipped for MACS

390

of 1,024 the progression makes

Progression for each position

Cuts each position steps through, after the TMK cut
Position	1	2	3	4	5
TMK	3	5	3	5	3
Change cuts	5 7 9 1	7 9 1 3	5 7 9 1	7 9 1 3	5 7 9 1

Total position progression: every position steps through the cuts listed, the last position fastest. No change key shares a cut with the TMK, so no change key opens another unit's lock.

Key schedule

Type a door or room for each key. It goes on the printout. Pins are bottom + master for each chamber, chamber 1 nearest the bow.

Key schedule: Example: Oak Street Apartments

Date: ______________

Schlage 5-pin (SC1). Two-level system, total position progression, two-step. Schlage top pins: #1 for a stack of 0 to 3, #2 for 4 to 6, #3 for 7 to 9.

Key schedule
Key	Bitting	Door or room	Pins (bottom + master)
A (TMK)	35353	All doors	Opens every lock below
A1	57575	Unit 1	3+2 5+2 3+2 5+2 3+2
A2	57577	Unit 2	3+2 5+2 3+2 5+2 3+4
A3	57579	Unit 3	3+2 5+2 3+2 5+2 3+6
A4	57571	______________	3+2 5+2 3+2 5+2 1+2
A5	57595	______________	3+2 5+2 3+2 5+4 3+2
A6	57597	______________	3+2 5+2 3+2 5+4 3+4
A7	57599	______________	3+2 5+2 3+2 5+4 3+6
A8	57515	______________	3+2 5+2 3+2 1+4 3+2
A9	57517	______________	3+2 5+2 3+2 1+4 3+4
A10	57511	______________	3+2 5+2 3+2 1+4 1+2

Check against your manufacturer's pinning chart. Keep this schedule locked away: it opens every door in the system. Made with the free master key planner at lockcommand.com/tools.

Bill the building for the rekey on site with an invoice and a pay link into your own Stripe, Square or PayPal.

Invoice the rekey in LockCommand

How to use it

This is for small jobs: a fourplex, a small office, a row of storage units. One top master key (TMK) opens every lock, and each door gets its own change key. That's a two-level system. For grand masters, cross keying or a campus, use proper master keying software and a key bitting array you keep on file.

How the change keys are made

The planner uses total position progression (TPP). Every position on a change key is cut to something other than the TMK cut in that position. With two-step progression it only uses cuts an even number of steps away from the TMK cut. On a Schlage, if the TMK has a 3 in position 1, the change keys use 5, 7, 9 or 1 there.

Each position gets a list of change cuts, counted up from the TMK cut and then wrapping round to the shallow ones.
The keys are listed in order with the last position changing fastest, like an odometer.
Any key that breaks MACS is skipped. So is any key that matches the TMK.
The first keys that pass become A1, A2, A3 and so on, under the TMK, which is A.

Because no change key shares a cut with the TMK in any position, no change key opens another door's lock. Each lock only takes the TMK cut or its own cut in every chamber. The order only decides which keys come first. It doesn't change which keys are safe.

Choosing the TMK

Cuts near the middle of the range leave the most room. A Schlage TMK of 3-5-3-5-3 gives four change cuts in every position, 1,024 keys before MACS and 634 after it. A Kwikset TMK gives fewer: change keys stay within cuts 1 to 6, since Kwikset reserves #7 for builders' keys, so two-step leaves two or three cuts per position. Kwikset kits carry #1 master pins, so the planner lets you pick single-step for Kwikset if you need more keys. Schlage stays two-step, because Schlage makes no #1 master pin.

A worked example

Schlage 5-pin, TMK 35353, two-step. Position 1 progresses through 5, 7, 9, 1 and position 2 through 7, 9, 1, 3. The first change keys are 57575, 57577, 57579 and 57571. Lock A1 gets bottom pins 3-5-3-5-3 and master pins 2-2-2-2-2. The TMK lifts every chamber to the top of its bottom pin. A1 lifts each one to the top of the master pin.

The schedule

Type a door or room next to each key and print the schedule. It lists every key symbol, bitting and pin stack. Treat it like the keys themselves: it opens every door in the building.

Sources

Last checked October 2026.

Locksmith Ledger, The Concepts and Mechanics of Master Keying: four change cuts per column in a two-step system, and TMK cuts kept out of the change cells to stop interchange.
Schlage, Primus service manual and Allegion's Combinating Rule 15 article: two-step progression, MACS 7, master pins from #2.
Kwikset, Rekeying with Kwikset Locks: master pins #1 to #6, #7 for builders' keys, .160" top pins when master keyed.
Tyler J. Thomas, Key Bitting Specifications (2025): Kwikset MACS 4.

Check against your manufacturer's pinning chart before you pin the first cylinder.

Questions

What progression does the planner use?

Total position progression. Every position on every change key differs from the top master key, two steps at a time for Schlage, and two or one step at a time for Kwikset.

Can one tenant's key open a neighbour's door?

Not between the change keys it makes. Each lock accepts only the master cut or its own cut in each chamber, and no change key uses the master cut in any position, so two different change keys can't open each other's locks.

Why did I get fewer change keys than I asked for?

The master key you picked leaves too few cuts, or too many combinations break MACS. Move the master key's cuts toward the middle of the depth range and try again.

Can it plan grand master or cross keyed systems?

No. It plans two-level systems only. Bigger systems need a key bitting array kept on file and master keying software, so changes years later don't clash with keys already out there.

Does it save my system anywhere?

No. Everything stays in your browser and disappears when you close the page. Print the schedule or save it as a PDF.

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