Need to know how many square feet you’re working with? Whether you’re buying flooring, ordering tiles, painting a wall, or pricing a plot, it all starts with one number: the area.
Square Feet & Area Calculator
Calculate room, floor, wall and irregular areas in square feet, square meters and square yards.
This square feet calculator does the maths for you. Punch in your measurements, pick your unit, and you get a clean answer in square feet, square metres, square yards, and more. No sign-up, no spreadsheet, no getting lost in conversions.
Below the tool you’ll find how to measure each type of space properly, how the units convert, and the small mistakes that trip people up. Let’s get into it.
What “area” actually means
Area is the amount of flat surface inside a boundary. For a floor, it’s the space you’ll cover with tiles or planks. For a wall, it’s what you’ll paint or tile. For a plot, it’s the ground it takes up.
The catch is that surfaces come in different shapes, and each shape has its own way of being measured. A square room is easy. An L-shaped hall, a round table top, or an odd four-sided plot needs a bit more thought. That’s exactly what the calculator handles.
The unit you measure in doesn’t change the space — it just changes the number. Ten feet is the same distance whether you call it 3.05 metres or 120 inches. The area comes out the same once you convert. More on that below.
How to use the square feet calculator
The tool is built to match how people actually measure, so pick the option that fits your space:
- Rectangle — most rooms and floors. Enter length and width.
- Square — one side length, and it does the rest.
- Multiple areas — add several rooms and it totals them into one figure. Ideal for a whole house or an L-shaped layout split into two rectangles.
- Wall area — add each wall, then deduct doors and windows so you’re not paying to tile thin air.
- 4, 5 and 6-sided shapes — for irregular plots and rooms. You measure the sides plus a couple of diagonals from one corner, and it splits the shape into triangles to find the true area.
- Circle — enter the radius for round tables, patios, or feature areas.
- Triangle — enter three sides; it uses Heron’s formula.
Choose a unit (feet, inches, yards, metres, centimetres or millimetres), enter your numbers, and hit calculate. Then use Show result in to flip the headline between square feet, square metres, square yards, square inches, square centimetres, acres or hectares — it updates instantly.
Once you’ve got your area, you’re ready to work out materials. Send the figure straight into the tile calculator to get boxes of tiles, or the tile cost estimate calculator to build a rough budget.
Measuring by shape: a quick guide
Here’s the short version of how to measure each type of space so your numbers come out right.
| Shape | What to measure | How the area is found |
|---|---|---|
| Rectangle | Length and width | Length × width |
| Square | One side | Side × side |
| Multiple rooms | Length and width of each | Each area added together |
| Wall | Length and height of each wall | Walls added, openings deducted |
| Circle | Radius (centre to edge) | π × radius × radius |
| Triangle | All three sides | Heron’s formula |
| 4 / 5 / 6-sided | Each side + diagonals from one corner | Split into triangles, then added |
For the irregular shapes, the golden rule is to measure every diagonal from the same corner — the one shown in the diagram. That’s what lets the tool break the shape into triangles correctly. Measure diagonals from random corners and the answer won’t be reliable.
Getting the measurements right
The calculator is only as good as the numbers you feed it. A few habits from the trade:
Measure twice. It sounds obvious, but a single fat-fingered number throws off the whole order. Check each length before you move on.
Measure the widest points. Rooms are rarely perfectly square. Measure where the wall is longest and widest so you don’t come up short.
Keep the tape straight. A sagging or angled tape reads longer than the real distance. Pull it taut and level.
Work in one unit per measurement. Don’t mix feet and inches in your head — enter feet in the feet field, or switch the tool to inches. Let the calculator convert.
Round up, not down. When a measurement falls between two marks, round up. It’s cheaper to have a little spare than to run out mid-job.
Understanding the units
Different countries measure area differently. The US leans on square feet and acres, the UK and Europe use square metres and hectares, and a lot of buying and selling in South Asia happens in square feet too. Here’s how the common ones line up.
| Unit | Equal to | Best for |
|---|---|---|
| 1 square foot | 144 square inches | Rooms, tiling, flooring |
| 1 square yard | 9 square feet | Carpet, some fabric and paving |
| 1 square metre | about 10.76 square feet | Metric flooring and tiles |
| 1 square metre | 10,000 square centimetres | Small surfaces, detailed work |
| 1 acre | 43,560 square feet | Land and plots |
| 1 hectare | 10,000 square metres | Large land parcels |
The calculator shows all of these at once after you calculate, so you never have to reach for a conversion chart. Handy when your tiles are sold in square metres but your plot was quoted in square feet.
Don’t forget wall area and deductions
Floors get most of the attention, but walls matter just as much for tiling and painting. Bathrooms and kitchens especially.
The trick with walls is deductions. You don’t tile over a doorway or a window, so those areas come off the total. The Wall area mode lets you add each wall, then list your doors and windows to subtract them. What’s left is the real surface you’ll cover.
Skip the deductions and you’ll over-order — sometimes badly, in a small bathroom where a door and window eat up a big share of one wall.
Why add a wastage margin
The area you measure is the finished surface. The amount you actually buy should be a little more.
Cuts, breakages, corners, pattern matching, and the odd cracked tile all eat into your stock. That’s wastage, and it’s normal. Most jobs add somewhere in the range of 5% to 10% on top; intricate layouts, diagonal patterns, or large-format tiles with more cutting can need more.
The calculator keeps wastage optional and set to zero by default, so the headline number is your true area. When you’re ready to order, add a margin and it shows you the padded figure alongside the base. If you want to think this through properly, the tile cost estimate calculator factors wastage into the numbers too.
From area to materials
Knowing your square footage is step one. Turning it into an order is step two, and the area figure feeds straight into the rest of the toolkit:
- Tiles: drop your area into the tile calculator to get boxes, with wastage built in.
- Adhesive and grout: once you know your area and tile size, the tile adhesive calculator and grout calculator tell you how many bags and packs.
- Stone: for granite and marble work, the how to calculate marble quantity guide walks through slabs and running feet.
One clean area measurement, and the whole material list falls into place.
Bottom line
Area is the foundation of every flooring, tiling, painting, and planning job — get it right and everything downstream gets easier. This square feet calculator handles the shapes real rooms and plots come in, converts between every common unit instantly, and lets you add a wastage margin when it’s time to buy.
Measure carefully, measure the widest points, keep your diagonals from one corner on odd shapes, and round up when in doubt. Then let the tool do the arithmetic. Once you’ve got your number, the tile calculator and tile cost estimate calculator take you the rest of the way.
Frequently asked questions
How do I calculate square feet of a room? Measure the length and width of the room in feet, then multiply them. A room 12 feet by 14 feet is 168 square feet. For rooms that aren’t simple rectangles, use the multiple-areas or irregular-shape options in the calculator so the odd corners are counted properly.
How do I calculate square footage from inches, metres or centimetres? Enter your measurement in its own unit — the calculator has feet, inches, yards, metres, centimetres and millimetres — and it converts for you. You don’t need to do any maths by hand. If you’d rather see the result in metres or yards instead of feet, use the “Show result in” option.
How many square feet are in a square metre? One square metre is about 10.76 square feet. So a 20-square-metre room is roughly 215 square feet. The calculator shows both figures side by side after you calculate.
How do I measure an irregular or odd-shaped room? Pick the 4, 5, or 6-sided option to match the number of sides. Measure each side, then measure the diagonals from the single corner marked in the diagram. The tool splits the shape into triangles and adds them for the true area. Measuring all diagonals from the same corner is the key to an accurate result.
How do I calculate wall area for tiling? Use the wall-area mode. Add the length and height of each wall, then list your doors and windows so they’re deducted. The result is the actual surface you’ll tile, without paying for openings you won’t cover.
How much extra should I add for wastage? A margin of about 5% to 10% suits most straightforward jobs. Add more for diagonal layouts, busy patterns, or large tiles that need a lot of cutting. The calculator lets you add this margin and shows the padded amount next to your base area.
What’s the difference between square feet and square yards? One square yard equals nine square feet. Carpet and some paving are often sold by the square yard, while tiles and flooring usually go by the square foot or square metre. The calculator displays all of these together so you can match whatever your supplier uses.
Can I use this calculator for land or plot area? Yes. For plots, measure the boundary sides and diagonals and use the irregular-shape options, then switch “Show result in” to acres or hectares for land-sized figures.