Measuring Guide
How to measure a rough opening for a quote.
You do not need perfect numbers to get started—we field-verify before production. But good measurements make your quote more accurate and your shop drawings faster.
Step by step
Measure width, height, and depth. Three times each.
Step 1
Identify what you are measuring
For new construction, measure the rough opening (the framed hole in the wall). For replacement, measure the existing frame opening, or the rough opening if the old frame will be removed. Tell us which one you measured.
Step 2
Measure width in three places
Top, middle, and bottom of the opening, inside edge to inside edge. Record all three. We will use the smallest to size the unit.
Step 3
Measure height in three places
Left, center, and right, from the sill (bottom) to the head (top). Again, record all three; the smallest governs.
Step 4
Measure wall depth
From the interior finished surface to the exterior finished surface. This determines frame depth, extension jambs, and sill details.
Step 5
Check for square and level
Measure both diagonals; if they differ by more than ½", note it. Place a level on the sill. Out-of-square openings are common in older homes and are fine—we just need to know.
Step 6
Note obstructions and context
Interior trim, radiators, countertops, exterior siding type, floor level at doors, and anything that affects how the unit opens. Photos help enormously.
Replacement windows
Measure the existing frame opening (inside the old frame) if the new unit will fit inside, or the rough opening if the old frame comes out. Tell us which. Photos of the exterior trim help us recommend the right approach.
Doors & thresholds
Measure from finished floor (inside) to the head of the opening and note the exterior grade or deck height. Low-threshold lift-and-slide sills need a recess—we will detail it in shop drawings.
Commercial schedules
Pro accounts can upload a window schedule with opening IDs, widths, heights, and types. Download our template from the Pro portal to match our columns.
Next step
Not confident in your numbers? That is fine.
Send approximate sizes and photos. We confirm every dimension before anything is built.