Room Measurement Calculator
🇦🇺 Australia version
Before the tiler or the flooring supplier quotes, you need the area of each room in square metres and the length around its walls. This version starts in metres, deducts doors and windows, adds up as many rooms as you list, and turns the surface you choose into boxes with a waste margin.
Use Room Measurement Calculator online
Room Measurement Calculator
Work out floor area, wall area, perimeter and volume for every room in a project, deduct doors and windows, and turn the totals into a materials order.
Australia rules and figures
- Australian floor plans and flooring quotes use square metres, so the page opens in metres and m² rather than feet.
- Boxes start at a 2 m² cover and 10% waste, which are placeholders for the pack size and layout you actually have.
- GST of 10% is included in shelf prices in Australia, so the price per box you type needs no tax added.
- The country’s standard unit for lengths in this tool is metres, with room heights typed as decimals such as 2.7.
Sources: ATO: Australian Taxation Office (GST rate) (checked 2026-11-08)
How the Room Measurement Calculator works
Each room is treated as a rectangle with a flat ceiling. Dimensions are read in metres, openings come off the four walls, and the materials tab rounds the allowance-adjusted area up to whole boxes.
floor = L × W; perimeter = 2(L + W); wall = perimeter × H − openings; boxes = ceil(area × (1 + waste ÷ 100) ÷ box cover)
- Two example rooms load first, measuring 5.5 × 4.3 m and 3.7 × 3.4 m, each under a 2.7 m ceiling and with its own doors and windows.
- A door added with + Door starts at 0.81 × 2.03 m and a window at 0.9 × 1.2 m, which you can overwrite with real sizes.
- Waste starts at 10% and a box at 2 m². Straight-laid tiles often use 5%, and the Tile 5% preset sets it in one click.
- Nothing is priced until you enter a price per box, and the tool does not add GST, delivery or discounts.
How to use the Room Measurement Calculator
- List your rooms. Put each room’s length, width and ceiling height in metres. Use Add room for a kitchen, hall or ensuite.
- Add the openings. Choose + Door or + Window inside a room and set each opening’s size and count, so wall area is net.
- Review the totals. The Totals tab shows floor area, ceiling, net wall, volume and total perimeter for every room you entered.
- Plan the order. On Materials choose Floor, apply the waste for your layout, and enter the box cover and price in dollars.
- Hand it over. Copy summary is handy for an email to the supplier, and Export CSV saves each room’s numbers.
Example: A 5.5 × 4.3 m living room tiled with 5% waste
With a 2.7 m ceiling, 2 doors and 2 windows, the living room has 23.65 m² of floor, a 19.60 m perimeter, 52.92 m² of gross wall and 7.25 m² of openings. That leaves 45.67 m² of net wall and 63.85 m³ of volume. Tiles at 5% waste need 24.83 m², which is 13 boxes covering 2 m² each, with 1.17 m² spare.
When to use the Room Measurement Calculator
- Tiling a bathroom or living area. Enter the room, pick floor, apply 5% waste, and read the number of boxes of tiles.
- Quoting for a painter. Use the gross wall area and ceiling area from Totals to brief the painter.
- Planning timber floorboards. Use the floor area with a higher waste for diagonal laying and see the extra boxes.
- Estimating air-conditioner size. Read the room volume in cubic metres as one input before comparing models.
What the Room Measurement Calculator does not do
- Switching units converts the typed sizes (rounded to 4 decimals), so flipping back and forth can leave tiny rounding differences. Metric and feet-and-inches shorthand cannot be mixed: inch shorthand is read only in feet mode.
- Rooms are rectangles with flat ceilings. For an L-shape, add two rooms; sloping ceilings need an average height.
- The Materials tab prices whole units only, so the cost is units times the price you enter, with no discounts, tax or delivery. Outside the US no starting price is filled in.
- Opening areas ignore frames and reveals, and every door or window you add uses a typed size, not a catalogue size.
- Measure real rooms at several points: the tool trusts the one number you type for each side.
When something else is a better fit
- When you are estimating paint and want coats, texture and colour change built in, use the Paint Calculator.
- When you need to convert measurements between feet, metres and inches, use the Unit Converter.
- When the room is irregular or you need a scaled drawing, use a floor-plan or CAD app, or a laser measure with a sketch.
Questions about the Room Measurement Calculator
How many boxes of tiles does a 5.5 by 4.3 metre room need?
13 boxes of 2 m² at 5% waste. The floor is 23.65 m², which becomes 24.83 m² with the allowance. Change the box cover to match your tiles and the count updates.
Does the tool work in feet if I have an old plan?
Yes. Open Display units, pick feet and square feet, and the typed numbers convert. Feet-and-inches shorthand such as 12'6" is read only in that mode.
What happens to doors and windows?
They are deducted from the gross wall to give net wall, using the sizes and counts you enter. A room cannot show negative wall: the deduction stops at the gross area.
Is GST included in the cost?
Only if your price includes it, and Australian shelf prices do. The tool multiplies whole boxes by the price you type and adds no delivery or tax.
Are my rooms saved?
Yes, in this browser only. Reloading keeps them, a removed room goes to Recently deleted, and Reset keeps the old list as a saved version after you confirm.