Square footage calculator
Type the length and the width the way your tape measure reads them. Try 12, 12.5, 12'6", 12 ft 6 in or 3.5 m.
A tape reading good to an inch either way makes a 12 × 10 ft room anything from 118 to 122 sq ft. Set what your measurements are good to and the total says so — and the estimators order for the top of the range, because ordering for the middle is ordering too little half the time.
Bigger boxes, Enter for the next measurement, and the screen kept awake — for measuring with a tape or a laser meter in hand.
Rooms
Cutouts (taken off)
Photo notes
Extra areas (added on)
A cutout's area comes off the room. Draw one in the floor plan editor and it keeps its place as well.
Show how this was worked out
Room 1
12 × 12 = 144 ft²
1 room counted: 144 ft²
Waste and cost
- Area to buy
- 158.4 ft²
Add a price to see the cost.
Materials only — labour, delivery and fittings are not included.
Make a quote for a client
Check a quote
Work the whole house out to the ANSI Z765 standard, with these rooms
Share this calculation
The link holds the measurements themselves, so it opens the same calculation on any device.
Recent calculations
Calculations you make are listed here, on this device only.
What the result means
The total is the floor area of the rooms you entered: what you would cover with flooring, tile or carpet. It is measured inside the walls, with cutouts taken off and extra areas added on, and it is shown in square feet, square metres, square yards, acres and hectares at once so you can hand the number to whoever needs it in whichever unit they use.
The per-room lines show the working — 12 × 10 = 120 — so a number you did not expect can be traced
back to the measurement that caused it, and Show how this was worked out lays the whole
calculation out in order: every room’s formula, every cutout taken off by name, and the running
total as each room joins it.
What to do next
- Buying flooring or tile? Open Waste and cost above and add a waste percentage: about 10% for a straight layout, 15% or more for diagonals and herringbone. The panel multiplies the area with waste by your price, so you get both the quantity to order and what it will cost.
- Not a rectangle? Change the shape, or add a room for each part and let the total add them up. The measuring guide walks through splitting an L-shaped room.
- Corners not square? Pick Four walls + diagonal and measure one line corner to corner: four wall lengths alone do not fix a room’s area, and that diagonal does. Measure the second diagonal too and the calculator checks your corners against each other and names the one that is out.
- Need to send it to someone? Copy link puts the whole calculation in the address — measurements and all — so it opens exactly as you left it on any device. Print or save as PDF gives a one-page summary with the room table and the drawings.
- Is that a big room or a small one? The room sizes pages set a bedroom, a kitchen, a living room and a garage against the building codes and the survey data.
- Checking someone else’s figure? The methodology page lists every formula, the exact conversion constants and how rounding is handled.
Measuring tips that change the answer
- Measure at floor level, wall to wall, not across furniture.
- Include alcoves and bay windows; leave out anything fixed that sits on the floor, like a kitchen island or a staircase opening.
- Keep the decimals until the end. Rounding each room before adding them is how a job ends up a box of tiles short.
- Measure in the unit you will buy in, and let the calculator convert for the people who need the other one.