To measure a house for a floor plan, you work from the outside in: first the exterior perimeter, then each room, then the details such as doors, windows and ceiling heights. A systematic approach is faster and much more accurate than measuring rooms at random. Done well, your measurements can be turned into permit-quality drawings without a return visit.
Quick answer: Measure the exterior walls first and sketch the outline. Then measure each room wall-to-wall in both directions, record wall thicknesses at doorways, locate doors and windows from a corner with their widths and heights, note sill heights and ceiling heights, and photograph everything. Finally, check that room dimensions plus walls add up to the exterior dimensions.
Tools you need to measure a house for a floor plan
- Laser distance measure, for long and room dimensions.
- 25-foot tape measure, for openings, sills and short dimensions.
- 100-foot tape or wheel, for exterior walls.
- Graph paper or a tablet sketch app, plus a pencil.
- Phone camera.
- Painter’s tape or sticky notes, to label rooms in photos.
- A helper, for long exterior runs.
Our pillar on floor plans for permits explains what the finished plan needs to show.
Step 1: Sketch the outline
Walk around the house and sketch the footprint, including every bump-out, bay, chimney, porch and garage. It doesn’t need to be to scale; it needs every corner. Number the walls clockwise so you can label measurements.
Step 2: Measure the exterior
Measure each exterior wall from corner to corner at the same height, usually the foundation or siding just above it. Record each on the sketch. Measure projections such as bays and chimneys, and note where porches and decks attach. On a simple rectangle, opposite sides should match; on complex shapes, the sum of the jogs on one side should equal the opposite side.
Step 3: Measure each room
Work through the house room by room, sketching each with its walls, doors and windows. For each room:
- Measure wall to wall in both directions, at about waist height, avoiding baseboards.
- Measure any jogs, closets and alcoves.
- Locate each door and window by measuring from the nearest corner to the edge of the opening, then the opening width.
- Record door swing direction.
- Note fixed features: fireplaces, built-ins, stairs, columns.
Measure diagonals in rooms that may be out of square; if the two diagonals differ significantly, note it.
Step 4: Wall thicknesses
Wall thickness is the most commonly missed measurement, and without it dimensions won’t close. Measure at door openings, where both faces are visible. Typical interior walls are about 4½ to 5 inches finished; exterior walls vary with framing, sheathing and siding. Measure each type you find.
Step 5: Windows and egress details
- Window width and height (frame or rough opening, state which).
- Sill height above the floor, important for bedroom egress; see egress window requirements.
- Window type: double-hung, casement, slider, fixed.
- For egress, the clear opening when fully open.
Step 6: Ceiling heights and vertical features
Measure ceiling height in each room, and note sloped ceilings, soffits, beams and ducts, especially in basements and attics where minimum heights matter. Measure stair total rise, the number of risers and tread depth.
Step 7: Fixtures and equipment
Locate plumbing fixtures, kitchen appliances, cabinets, the furnace, water heater and electrical panel. Approximate positions are often enough unless the project changes them.
Step 8: Photos
Photograph each room from two opposite corners, each wall with openings, the exterior from all sides, and equipment. Photos answer questions later and help the drafter interpret the sketch.
Step 9: Check that dimensions close
Along each line through the house, add room widths and wall thicknesses and compare with the exterior dimension. A difference of more than an inch or two means something was missed: usually a wall thickness, a closet or a chase. Fix it while you are still on site.
Common mistakes
| Mistake | Fix |
|---|---|
| Skipping wall thicknesses | Measure at every door opening |
| Measuring over baseboards or furniture | Measure at waist height, wall to wall |
| Estimating window positions | Measure from the nearest corner |
| Forgetting closets and chases | Sketch every recess |
| Missing ceiling height changes | Measure each room and note soffits |
| Not checking closure on site | Add up strings before you leave |
Measuring for specific projects
For an addition, measure the wall where it will attach in detail, including window and door positions and the roof eave height. For a basement finish, measure ceiling heights under beams and ducts. For a garage conversion, measure the slab slope and the height of the slab relative to the house floor. For a load-bearing wall removal, note the joist direction where visible; see load-bearing wall removal.
Measuring for exterior elevations
If you also need elevations, record heights while you are outside: the foundation height above grade, the eave height, the ridge height (a laser can measure this from inside the attic or by angle from the ground), window head and sill heights, and the roof pitch. Photographs of each side, taken square to the wall, help the drafter place windows and trim. See roof pitch explained for how to measure the slope.
Turning measurements into drawings
A drafter turns your sketch and numbers into a scaled as-built floor plan. Our floor plans service works from homeowner measurements and photos, and flags any dimensions that don’t close so you can check them. For exterior views, the same measurements, plus heights, feed elevation drawings.
Frequently asked questions
How do I measure a house for a floor plan: inside or outside first?
Outside first. The exterior outline gives a frame to check interior measurements against.
How accurate do my measurements need to be?
To the nearest half inch to inch for most permit work, with egress windows and stairs measured carefully.
Do I need a laser measure?
Not essential, but it makes room measuring faster and more accurate, especially working alone.
How do I measure wall thickness?
At a door opening, from one wall face to the other.
How long does it take to measure a house?
Often two to four hours for a typical home, longer for complex or larger houses.
