How to use the cabinet door size calculator
- Choose inches or millimeters and enter the width and height of the opening, measured between the cabinet sides and between the top and bottom.
- Pick the door style. Overlay doors cover the edge of the cabinet, and inset doors sit inside the opening.
- Enter the overlay (how far an overlay door covers the edge on each side) or the reveal (the space around an inset door), the number of doors across and the gap between doors.
- Read the width and height to cut each door. For inches, the result is also shown to the nearest sixteenth.
Formula
overlay doors: total width = opening + 2 x overlay, total height = opening height + 2 x overlay
inset doors: total width = opening - 2 x reveal, total height = opening height - 2 x reveal
width of each door = (total width - (doors - 1) x gap) / doors
check: doors x door width + (doors - 1) x gap = total width
The same overlay is used on all four sides. If your hinges need a different overlay at the top and bottom, work out the height on its own.
A 30 inch by 30 inch opening
With full overlay doors of 3/4 inch (0.75) and a pair of doors with a 1/8 inch gap, the total width is 30 + 1.5 = 31.5 inches. Each door is (31.5 - 0.125) / 2 = 15.6875 inches (15 11/16) wide and 31.5 inches (31 1/2) high. A single door with a half overlay of 3/8 inch is 30.75 inches wide. Three doors across the same opening are each 10.4167 inches (about 10 7/16) wide.
Inset doors with a 1/8 inch reveal and a 1/8 inch gap between a pair are each (30 - 0.25 - 0.125) / 2 = 14.8125 inches (14 13/16) wide and 29.75 inches (29 3/4) high. In millimeters, a 762 by 762 opening with 19 mm overlay and a 3 mm gap gives two doors 398.5 mm wide and 800 mm high.
Choosing the overlay
The overlay is set by the hinge and the cabinet. Frameless cabinets often use full overlay hinges, face-frame cabinets use half or partial overlay hinges, and inset doors need hinges made for them. Check the hinge instructions before cutting, because the right overlay is a property of the hardware. The values in this tool are examples.
Before you cut
Measure the opening in several places and use the smallest, since cabinets are rarely perfectly square. Cut one door first and test it. Allow for how the finish adds a little thickness at the edges. For shelves behind the doors, see the Shelf Spacing Calculator, and for the lumber, the Board Foot Calculator.
More tools for the workshop and home
For related projects around the house and workshop, try the Pond Liner Size Calculator, Firewood Cord Calculator and Fabric Shrinkage Calculator.
Assumptions and limits
- The same overlay or reveal applies on all four sides of the opening.
- The doors are flat and rectangular, with no extra width for rails or stiles in the sizing.
- The gap between doors is the same for every pair.
- The opening is square and measured at its narrowest point.
- The opening, overlay and gap in the form are examples. Use the figures for your own cabinet and hinges.
Frequently asked questions
What is the difference between overlay and inset doors?
An overlay door lies in front of the cabinet and covers part of the edge. An inset door sits inside the opening, flush with the face, and needs a tight, even fit all around.
Why is there a gap between a pair of doors?
Doors that touch would rub when they open and close. A small gap, often an eighth of an inch, lets them swing freely and allows for the wood moving with the weather.
Can I use this for drawer fronts?
Yes. A drawer front is sized the same way as a single overlay or inset door, using the width and height of its opening.
Why does the page show fractions of an inch?
Tape measures and plans use sixteenths of an inch. The tool rounds to the nearest sixteenth for reading, but the exact decimal is also shown so you can cut precisely.