The math is shown
Every calculator publishes its formula and a worked example, so you can check the result before you spend money on materials.
Free renovation calculators
Measure once.
Measure once.
Buy the right amount.
Figure out exactly how many tiles, how much paint, how many bags of concrete or boxes of flooring to buy — and what it'll cost. 35 free calculators, each showing its formula, with wastage handled properly in metric or imperial.
Pick a tool
All calculators
35 material calculators, each with its formula shown and wastage handled. More on the way.
Walls, floors & interior
Finish a room - tiling, flooring, painting, papering and boarding.
Square Metre Area Calculator
Total area of any room or plot in m², sq ft, sq yd and hectares.
Open calculator→Tile Calculator
How many tiles, boxes, adhesive and grout to buy for a floor or wall, with wastage and cost built in.
Open calculator→Paint Calculator
Litres of paint for walls and ceilings, with coats and coverage built in.
Open calculator→Wallpaper Calculator
How many rolls of wallpaper to buy for a room, with the pattern repeat built in.
Open calculator→Boiler Replacement Cost Calculator
UK cost bands for a new boiler or an air source heat pump, by type, conversion and kW - grant included.
Open calculator→Flooring Calculator
Planks and boxes of laminate, vinyl or hardwood flooring, with layout wastage.
Open calculator→Carpet Calculator
Linear metres of broadloom carpet to buy from your room sizes and roll width.
Open calculator→Garage Floor Paint & Epoxy Calculator
Garage floor paint or epoxy, kits and cost - DIY or professionally applied.
Open calculator→Skirting Board Calculator
Linear metres of skirting board and how many stock lengths to buy.
Open calculator→Stud Wall Calculator
Studs, plate/track and plasterboard sheets for a partition wall, with cost built in.
Open calculator→Board Foot & Timber Volume Calculator
Board feet, volume and cost for any number of timber sizes.
Open calculator→Plasterboard Calculator
Plasterboard sheets, screws, jointing compound and tape to board and finish a room.
Open calculator→Loft & Wall Insulation Calculator
Rolls, batts or blown-in bags - and cost - to hit a target R-value for walls, loft and ceilings.
Open calculator→Outdoor & structures
Build outside - decks, fences, patios, steps and concrete.
Concrete Calculator
Cubic volume and bags of concrete for slabs, footings, pads and posts.
Open calculator→Concrete Mix Ratio Calculator
Cement, sand, aggregate and water for any concrete mix ratio.
Open calculator→Brick & Block Calculator
Bricks or blocks, plus mortar and sand, from your wall sizes and unit size.
Open calculator→Reinforcing Bar (Rebar) Calculator
Bars each way, total length, weight and ties for a slab or footing rebar grid.
Open calculator→Concrete Block Calculator
Concrete blocks (breeze or dense block), plus mortar and sand, from your wall sizes.
Open calculator→Decking Calculator
Deck boards, total board run and joists for a deck of any size.
Open calculator→Paving Calculator
Paving slabs or blocks, sub-base, bedding sand, jointing sand and cost for a patio or path.
Open calculator→Deck Tile Calculator
How many interlocking deck or patio tiles, packs and cost, with wastage built in.
Open calculator→Fence Calculator
Posts, rails, boards, bags of Postcrete and cost for a fence of any length.
Open calculator→Pipe Size & Friction Loss Calculator
Water velocity and friction loss for a pipe, from the flow, material and inside diameter.
Open calculator→Stair Calculator
Rise, run, risers, treads, stringer length and pitch - drawn as a diagram and checked against your country's stair code.
Open calculator→Roof Pitch & Rafter Length Calculator
Common rafter length, roof angle, slope and rise from any pitch.
Open calculator→Roof Shingle Calculator
Shingle bundles, roofing squares and underlayment from your roof area and pitch.
Open calculator→Cladding Calculator
Boxes of uPVC, or fibre-cement / timber cladding, plus trims and corner posts from your wall sizes.
Open calculator→Pool Volume Calculator
Pool volume in litres, cubic metres and imperial gallons.
Open calculator→Landscaping & soil
Fill and cover by volume - mulch, gravel, topsoil and garden beds.
Bark Chippings & Mulch Calculator
Volume and bags to cover beds with bark chippings or mulch at any depth.
Open calculator→Aggregate & Sub-Base Calculator
Volume and bags of gravel, MOT Type 1 or hardcore for driveways, paths and drainage.
Open calculator→Topsoil Calculator
Volume, litres and bags of topsoil for lawns, turf and garden beds.
Open calculator→Raised Bed Soil Calculator
Soil volume and bags to fill one or more raised garden beds, with mix ratios.
Open calculator→Turf & Grass Seed Calculator
Rolls and pallets of turf, or kilos and bags of grass seed, from your lawn size.
Open calculator→Irrigation & Watering Zone Calculator
Sprinkler heads, flow and the number of zones to plumb, from your garden size and water supply.
Open calculator→Retaining Wall Calculator
Blocks, caps and gravel base for a retaining wall, from your wall and block sizes.
Open calculator→
Advanced mode · built into every calculator
Try it on the tile calculator
Override the presets. Match your real job.
It's not a separate tool - every calculator already lets you go past the defaults. Set a custom waste percentage for your exact layout, and enter your own tile, plank, board, box and tin sizes, so the count reflects the materials you'll actually buy.
- Custom waste %
- Tile & plank sizes
- Box & tin sizes
- Per-layout allowances
Why these tools
Built like a takeoff sheet, not a toy
The same numbers an estimator would run by hand - transparent, unit-aware and rounded the way a real order is placed.
// TILE.FORMULA
area = 5.0 × 4.0 = 20.0 m²
per_tile = 0.6 × 0.6 = 0.36 m²
tiles = ⌈ 20 ÷ 0.36 × 1.10 ⌉
→ 61 tiles
Feet or metres, correctly
All calculations run in exact metric units internally and convert at the display layer - switching units never changes the answer.
Wastage built in, honestly
Layout-specific allowances (grid, offset, herringbone) instead of a vague “add some extra” - so you buy enough, once.