Home & DIY Calculators

Calculators for every stage of a project

Most home projects come down to three questions: how big is it, how much material do I need, and what will it cost? The calculators in this section answer those questions for the jobs people tackle most often around the house and garden.

• Concrete Calculator – Cubic yards, m³ and premix bag counts for slabs, footings, post holes and steps.
• Square Footage Calculator – Area of rooms and L-shapes in sq ft, m² and sq yd, with cut-outs and waste.
• Paint Calculator – Gallons or litres of paint for walls and ceilings, with doors and windows subtracted.
• Gravel Calculator – Cubic yards, tons, m³ and tonnes of gravel or crushed stone for any area.
• Cubic Yard Calculator – Cubic yards, cubic feet and m³ for soil, mulch, fill and more.
• Cubic Feet Calculator – Volume in ft³ with yd³, m³, litres and gallons.
• Board Foot Calculator – Board feet, cubic metres and cost for lumber.
• Stair Calculator – Risers, treads, run and stringer length, with code checks.
• Tile Calculator – Tiles and boxes for floors and walls, with waste.
• Flooring Calculator – Boxes of laminate, vinyl or hardwood for a room.
• Drywall Calculator – Sheets of drywall or plasterboard for walls and ceilings.
• Wallpaper Calculator – Drops and rolls of wallpaper, including pattern repeat.
• Brick Calculator – Bricks per ft² or m² and the total for a wall.
• Concrete Block Calculator – CMU, cinder or besser blocks for a wall.
• Roofing Calculator – Roof area, squares, bundles and tiles from footprint and pitch.
• Roof Pitch Calculator – Rise and run to x/12, degrees, percent and slope factor.
• Decking Calculator – Deck boards, joists and screws for a deck.
• Fence Calculator – Posts, panels, rails, pickets and post concrete.
• Insulation Calculator – Layers and packs to reach a target R-value or RSI.
• Voltage Drop Calculator – Volts and percent drop for AWG or mm² cable.
• Grout Calculator – Grout volume, weight and bags, plus thinset.
• Rebar Calculator – Bars, length, weight and ties for a slab grid.
• Feet and Inches to mm Converter – Feet, inches and fractions to mm and back.
• Dirt, Topsoil & Fill Dirt Calculator – Cubic yards, tons, bags and truckloads of dirt, topsoil or fill.
• Sand Calculator – Cubic yards, tons and bags of sand for any area and depth.
• Cubic Yards to Tons Calculator – Convert cubic yards to tons (and back) by material density.
• Lumber Calculator – Board feet, pieces, studs, joists and cost for a lumber order.
• Linear Feet Calculator – Add lengths, measure room trim and convert linear to square feet.
• Epoxy Calculator – Gallons of epoxy for floor coatings and resin pours, with A:B split.
• Mortar Calculator – Mortar volume, bags and site-mix quantities for brick, block and tile.
• Sod Calculator – Square feet, slabs or rolls, and pallets of sod for a new lawn.
• Asphalt Calculator – Tons of asphalt for a driveway, lot or road from area and thickness.
• Inches to Decimal Converter – Fractional inches to decimal inches, decimal feet and mm, and back.
• Paver Calculator – How many pavers, base stone and sand a patio or walkway needs.

How to get accurate results

Every calculator is only as good as the measurements you put in. A few habits make a big difference:

Measure in more than one place. Walls are rarely perfectly square, ground is rarely flat and excavations are rarely an even depth. Measure each dimension at least twice and use the larger figure, or average several depth readings.

Keep units consistent. Mixing feet and inches is the most common cause of wrong answers. Our imperial fields accept entries such as 12’ 6”, 12ft 6in or simply 12 6, and convert them to decimal feet for you. In metric, enter metres; 150 mm is 0.15 m.

Use the product’s own figures. Concrete bag yields, paint coverage and gravel density vary by manufacturer. The calculators start with sensible defaults, clearly labelled, but you can type in the figure printed on the bag, tin or supplier’s data sheet.

Allow for waste. Spillage, uneven ground, offcuts and over-excavation all eat into materials. Each calculator includes a waste or compaction allowance you can adjust. Running out mid-pour or mid-wall usually costs more than a bag or tin left over.

Imperial and metric, explained

CalcTen is built for readers in the United States, the United Kingdom, Australia and Canada, which between them use a mix of systems. The US works almost entirely in feet, inches, cubic yards, pounds and US gallons. The UK, Australia and Canada use metric officially, but feet and inches still appear in everyday conversation, in property listings and on some products.

Rather than forcing one system, every calculator has an Imperial/Metric switch and a region selector. The region changes the product sizes the calculator suggests: for example, 80 lb concrete bags in the US versus 25 kg bags in the UK and 20 kg bags in Australia, or 2.5 L and 5 L paint tins in the UK versus 4 L and 10 L cans in Australia. All conversions use exact definitions published by the US National Institute of Standards and Technology, such as 1 ft = 0.3048 m.

Which calculator should I use?

If you are pouring concrete, start with the concrete calculator for posts, steps and small pads, then add the rebar calculator if the slab needs reinforcement. Concrete is sold by volume (cubic yards or cubic metres) for ready-mix and by weight for bags, and the calculator shows both.

If you are laying flooring or carpet, use the square footage calculator, then add a waste allowance appropriate to your product and pattern.

If you are decorating, use the paint calculator. It works out wall area from the room’s floor dimensions and height, which is quicker than measuring every wall.

If you are landscaping, use the gravel calculator for stone and sub-base, the dirt and sand calculators for soil and bedding, and the sod calculator for a new lawn. Each gives volumes and, where a density is known, weights. For driveways, the asphalt calculator gives tons of hot mix, and for brickwork and tiling the mortar calculator covers bags of mortar and thin-set.

What’s coming next

We keep adding home and DIY tools as readers ask for them. Each new tool follows the same standard: tested logic, both unit systems, regional sizes, a worked example and cited sources. Use the contact page to suggest one.

A note on safety and building rules

These calculators help you estimate quantities. They do not replace professional design, local building codes or manufacturers’ instructions. Wet cement is alkaline and can cause burns, so wear gloves, eye protection and long sleeves; the UK Health and Safety Executive and product safety data sheets explain the risks. Older homes may contain lead paint or asbestos, so test before sanding or demolishing. For anything structural, including foundations, retaining walls and suspended floors, consult a qualified professional and check what permissions your local authority requires.

Frequently asked questions