Woodworking & Construction Calculators

Fine woodworking & cabinetry

Cabinet Door Sizing Calculator (Overlay vs Inset)

Overlay doors grow by the overlay on each edge. Inset doors shrink by the reveal. Pair doors share a centre gap. Rails run between the stiles.

Inputs

Units
in
in
in
in
in

Results

Doors
2
Door width
15.438in
Door height
25.000in
Rail length
10.938in
Stile length
25.000in

The Result is indicative and educational. It does not constitute a design, a technical opinion or medical advice and does not replace calculations or verification by a person with the appropriate qualifications and authorisations. Before purchase, installation or use in practice – in particular in electrical installations – the Result should be verified by a qualified specialist. Details: Terms of Service, point 4.

Example products

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Calculation method

Overlay adds to the opening; inset subtracts a reveal. A pair splits the remaining width after one centre gap. Rails are the short members between stiles, so rail length is door width minus two stile widths (no tenon extra).

Exact formula

Overlay: door height = opening + 2×overlay; one door is opening + 2×overlay wide, a pair (opening + 2×overlay − gap) / 2 each. Inset: door height = opening − 2×gap; one door is opening − 2×gap wide, a pair (opening − 3×gap) / 2 each. Rail length = door width − 2×stile width. Stile length = door height.

Metric casework

Openings, overlay, gap and stile width all convert between millimetres and inches, because each is a physical length; the door count does not change.

Frequently asked questions

What overlay should I use?

½ in (13 mm) is a common full overlay. Match the hinge plate you bought.

Do rails need extra for tenons?

This length is the shoulder-to-shoulder distance. If the tenons are cut on the rail itself, add both tenon lengths to the rail blank; with cope-and-stick bits add twice the cope depth instead.

Single vs pair?

Use a pair when the opening is too wide for one door to hang well, typically over about 24 in (610 mm).

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