Calculators

Square Metre Calculator

Calculate square metres (m²) of a rectangle, circle or triangle from measurements in mm, cm, m, inches, feet or yards, with an optional price per m².

£

Enter your values and press Calculate.

How to use the Square Metre calculator

Choose a shape, pick the unit you measured in and enter the sizes. The result is shown in square metres, square feet and square yards. Add a price per m² to cost flooring, turf, paving, tiles or decorating.

For an L-shaped room, split it into rectangles and use the multiple-room area calculator, or add the results together.

Formula

Rectangle: length × width. Circle: π × (diameter ÷ 2)². Triangle: ½ × base × height. Measurements are converted to metres first (1 ft = 0.3048 m), and 1 m² = 10.7639 sq ft.

Frequently asked questions

How do I work out square metres?

Multiply the length by the width, both in metres. A room 5 m by 4 m is 20 m². If you measured in centimetres, divide each by 100 first — this calculator does that for you.

More construction calculators

Square Footage CalculatorArea in square feet for any shape, with cost.Cubic Metre CalculatorVolume in m³ and litres, with cost.Cubic Feet CalculatorVolume in cubic feet, with cost.Multiple Room Area CalculatorTotal floor area of several rooms.Linear Metres & Linear Feet CalculatorTotal length of pieces and cost per metre or foot.Tank Volume CalculatorLitres and gallons in a rectangular or cylindrical tank.Concrete CalculatorConcrete volume and bags for a slab, in metric or imperial.Feet and Inches CalculatorAdd or subtract measurements in feet and inches.Paint CalculatorLitres or gallons of paint for a room.Tile CalculatorHow many tiles you need for a floor or wall.Mulch CalculatorVolume and bags of mulch or bark for a bed.Stair CalculatorRiser height, step count and stringer length.Drywall CalculatorSheets of drywall for walls and ceiling.Wallpaper CalculatorRolls of wallpaper needed for a room.Roof Pitch CalculatorRoof pitch, angle and slope from rise and run.Rafter Length CalculatorRafter length from span, pitch and overhang.Roofing Shingles CalculatorRoofing squares, shingle bundles and drip edge.Roof Sheathing CalculatorPlywood or OSB sheets for a roof deck.Fence CalculatorPosts, rails and pickets for a fence.Post Hole Concrete CalculatorConcrete bags to set fence or deck posts.Deck Board CalculatorNumber of deck boards and screws.Deck & Fence Stain CalculatorGallons of stain for a deck or fence.Baluster CalculatorNumber of balusters and spacing for a railing.Paver CalculatorNumber of pavers for a patio or path.Gravel, Sand & Soil CalculatorTonnes and volume of gravel, sand or soil.Cubic Yards CalculatorVolume in cubic yards from dimensions.Sod CalculatorPieces, pallets and rolls of sod for a lawn.Grass Seed CalculatorPounds of grass seed for new or overseeded lawns.Acreage CalculatorAcres and hectares from plot dimensions.Retaining Wall CalculatorBlocks and caps for a retaining wall.Pool Volume CalculatorGallons and litres of water in a pool.Board Foot CalculatorBoard feet of lumber and cost.Check Square CalculatorDiagonal measurement to square a corner or frame.Brick CalculatorNumber of bricks for a wall.Flooring CalculatorBoxes of laminate, vinyl or wood flooring.Scale CalculatorConvert real sizes to scale drawings and models.Concrete Column & Footing CalculatorConcrete for round columns (Sonotubes) and footings.