BuildCalc

BuildCalc

Free home improvement calculators that show the maths

30 free calculators for paint, tiles, concrete, roofing, lumber, landscaping and energy. Every one runs in your browser — nothing you type is uploaded, stored or tracked.

Free, private, no sign-up

Most used calculators

All 30 calculators →
Paint CalculatorHow much paint a room needs.Square Footage CalculatorArea of a room or a whole floor.Concrete CalculatorVolume of concrete for a slab or footing.Tile CalculatorHow many tiles to buy.Flooring CalculatorBoxes of laminate or vinyl plank.Drywall CalculatorSheets of drywall for a room.Roof Area CalculatorTrue roof area from the footprint and pitch.Mulch CalculatorBags or yards of mulch for a bed.Solar Panel CalculatorHow many solar panels your home needs.

Paint & walls

Category page →

Paint Calculator

How much paint a room needs.

Wallpaper Calculator

Rolls of wallpaper to buy.

Drywall Calculator

Sheets of drywall for a room.

Flooring

Category page →

Tile Calculator

How many tiles to buy.

Flooring Calculator

Boxes of laminate or vinyl plank.

Carpet Calculator

Carpet area and cost for a room.

Tile Grout Calculator

How much grout a tiling job needs.

Concrete & masonry

Category page →

Concrete Calculator

Volume of concrete for a slab or footing.

Brick Calculator

How many bricks a wall needs.

Mortar Calculator

Mortar mix for laying bricks or blocks.

Roofing

Category page →

Roof Area Calculator

True roof area from the footprint and pitch.

Shingle Calculator

Bundles of shingles for a roof.

Gutter Calculator

Gutter length, downspouts and sizing.

Lumber & framing

Category page →

Board Foot Calculator

Board feet in rough lumber.

Framing Lumber Calculator

Studs and plates for a framed wall.

Deck Board Calculator

Decking boards and joists for a deck.

Fence Calculator

Pickets, posts and rails for a fence.

Stair Calculator

Riser height, treads and stringer length.

Landscaping & yard

Category page →

Mulch Calculator

Bags or yards of mulch for a bed.

Topsoil Calculator

Volume of topsoil to fill or cover.

Sod Calculator

Rolls or pallets of sod for a lawn.

Gravel Calculator

Tonnage and volume of gravel.

Grass Seed Calculator

Seed rate for a new or patchy lawn.

Pool Volume Calculator

Gallons and litres a pool holds.

Room & area

Category page →

Square Footage Calculator

Area of a room or a whole floor.

Wall Area Calculator

Paintable or cladded wall area.

Energy & solar

Category page →

Solar Panel Calculator

How many solar panels your home needs.

Electricity Cost Calculator

What an appliance costs to run.

Air Conditioner BTU Calculator

Cooling capacity a room needs.

Insulation Calculator

Depth and bags of insulation for an area.

Guides

All guides →

Plain-English explainers on the questions behind the numbers — each one links to the calculator that answers it.

About BuildCalc

Free home improvement and DIY calculators for paint, wallpaper, drywall, tiles, flooring, carpet, concrete, bricks, mortar, roofing, shingles, gutters, lumber, decking, fencing, stairs, mulch, topsoil, sod, gravel, grass seed, pool volume, square footage, solar panels, electricity cost, air conditioning and insulation. Instant, private, no sign-up.

Each calculator explains the formula behind the number, how to read the result and where its limits lie — because a figure without context is not much use. Everything is calculated locally on your device, so sensitive numbers never leave your browser.

BuildCalc provides general, educational information only. It is not engineering, structural, electrical or building-code advice. Always check local regulations and consult a qualified professional before starting work.