How to Measure for Interior Doors: A Step-by-Step Guide
Measure slabs and rough openings correctly the first time with this step-by-step guide — essential for made-to-order doors.
Accurate measurements matter more than anything else when you buy doors online. Because our doors are made to order and all sales are final, five careful minutes with a tape measure saves you from an expensive mistake. Here is exactly how to do it.
What you will need
- A steel tape measure
- A level
- A notepad or your phone to record numbers
Measuring a slab (replacing an existing door)
Take the door off its hinges or measure it in place:
- Width: measure the door itself across the top, middle, and bottom. Use the largest number.
- Height: measure both edges and the center, top to bottom.
- Thickness: most are 1-3/8 inch; confirm with your tape.
- Hinges and hardware: note how many hinges, their positions, and the handle bore location and backset.
Measuring a rough opening (new construction or a frame replacement)
- Width: measure between the framing studs at top, middle, and bottom; use the smallest number.
- Height: measure from the subfloor to the header.
- Depth: measure the wall thickness so the jamb depth matches.
Check for square
Older Florida homes settle over time. Use your level on the jamb and the floor, and measure both diagonals of the opening — if they differ significantly, the opening is out of square and you should account for it or plan to shim during installation.
Double-check, then order
Write every number down, then measure a second time. If any measurement surprises you, send it to us before ordering. We would much rather confirm a size than have you receive a custom door that does not fit. Once you are confident, browse the full door catalog and configure your slab.