Room Square Footage Calculator
Measure the square footage of any room — bedrooms, living rooms, kitchens, bathrooms, or oddly-shaped spaces. Enter dimensions in feet and inches and see results in real time.
Room Calculator
How to measure a room
For a standard rectangular room, measure the length wall-to-wall along one side, then measure the width wall-to-wall along an adjacent side. Multiply the two together to get square footage.
For accuracy, measure each dimension at two points — once near the front of the room and once near the back. Older homes especially can taper by an inch or more across a single wall, which adds up over a full project.
Always measure to the inside of the wall surface (the finished wall), not to the studs. For flooring projects, measure to where you want the flooring to end — usually under the threshold of any doorway.
How to measure a room accurately
Most rooms are nominally rectangular but slightly off-square due to construction tolerances. The proper measurement approach:
Measure each wall at two points (top and bottom) and use the average. Walls bow slightly with age and settling.
Use a tape measure or laser distance tool. Laser tools are more accurate for distances over 12 ft, where tape sag introduces error.
Measure to the inside face of finished walls — not to the studs, not to the framing.
For rooms with closets, decide whether to include them (yes for material orders, depends on context for square footage reporting).
Verify with the diagonal: a 12 × 14 ft room should have a diagonal of √(144+196) = 18.44 ft. If your diagonal disagrees, one of the wall measurements is off.
Common room sizes and what's typical
Bedroom (small): 10 × 10 ft = 100 sq ft. Child's room or small guest room.
Bedroom (standard): 11 × 12 ft = 132 sq ft or 12 × 12 ft = 144 sq ft. Most US bedrooms.
Bedroom (large): 12 × 14 ft = 168 sq ft or 14 × 16 ft = 224 sq ft.
Master bedroom: 14 × 16 ft = 224 sq ft typical, up to 16 × 20 = 320 sq ft in luxury.
Living room: 12 × 18 ft = 216 sq ft or 15 × 20 ft = 300 sq ft typical.
Family room: 16 × 20 ft = 320 sq ft typical.
Kitchen: 10 × 12 ft = 120 sq ft (small) to 16 × 20 ft = 320 sq ft (large).
Dining room: 12 × 14 ft = 168 sq ft.
Full bath: 5 × 8 ft = 40 sq ft (minimum) to 10 × 12 ft = 120 sq ft (luxury).
Half bath / powder room: 4 × 5 ft = 20 sq ft.
Walk-in closet: 5 × 7 ft = 35 sq ft (small) to 10 × 12 ft = 120 sq ft (large).
Room area for different project types
Same room can need different square footage numbers depending on the project:
Flooring: room dimensions inside walls. Include closets if you want flooring in them.
Paint: wall area (perimeter × ceiling height) minus openings, not floor area.
Wallpaper: same as paint, plus pattern repeat waste.
Ceiling paint or wallpaper: equal to floor area, since ceilings match floors.
Tile (wall-tiled bathroom): wall area for the tiled portion only.
Crown molding: linear feet of perimeter, not square footage.
Baseboard: linear feet of perimeter minus doorways, not square footage.
Drywall: floor area + wall area + ceiling area, since drywall covers all of these.
Insulation: depends on what type — ceiling insulation = floor area, wall insulation = wall area.
Step-by-step measurement guide
Clear the perimeter
Move furniture away from the walls so your tape measure can run flush. Even a couple of inches of obstruction can throw off your reading.
Measure the length
Hook your tape on one wall, run it straight to the opposite wall. Note the measurement in feet and inches.
Measure the width
Repeat perpendicular to the length. Take the measurement at the widest point if the walls aren't perfectly parallel.
Multiply
Length × Width = Square Footage. Or just type your numbers into the calculator above and skip the math.
Add a waste factor
If you're ordering material, add 5–15% on top depending on the project type. The calculator does this for you when you select a material.
Pro tips
Measure feet AND inches
Don't round 12 ft 7 in down to 12 ft. Even small rounding errors add up across a whole room.
Sketch as you go
Draw the room shape and label each wall's measurement directly on the sketch. You'll catch mistakes faster.
Closets count for flooring
If you're buying flooring, include closets and any small alcoves — they need flooring too.
Subtract immovable obstacles
Built-ins, fireplaces, and floor-to-ceiling cabinets reduce the floorable area. Measure and subtract them.