Paint Calculator
Work out how much paint your walls need, minus doors and windows, with coats, an optional ceiling, and waste built in.
Open calculatorMaterial estimation for home projects
Know how much material your project needs.
Eleven free calculators for paint, flooring, concrete, drywall, tile, gravel, mulch, topsoil, sod, compost, and roofing. Each one turns your measurements into the quantities stores actually sell.
Waste allowances and purchase rounding are built in, units switch between US and metric, and prices come from you — nothing is invented. Every calculation runs in your browser.
11 calculatorsUS & metric unitsNo sign-upNothing stored
Calculators
Start with the work you are actually doing
Grouped by project type, so the calculator you need is one scan away. Every result is a live calculation from your own numbers — nothing is pre-filled with fake data, and prices come only from you.
Interior
Walls, floors & ceilings
Surface area, openings, coats, box coverage, and the waste that comes with cutting material to fit a room.
Interior calculatorsFlooring Calculator
Estimate boxes of flooring room by room — name each room, mix dimension and area input, and price the job per box.
Open calculatorDrywall Calculator
Estimate drywall sheets for a room — openings deducted, ceiling optional, any sheet size, with a waste allowance.
Open calculatorTile Calculator
Work out tiles or boxes for a floor or wall — fixtures deducted, any tile size, with a waste allowance for cuts.
Open calculatorOutdoor
Ground cover & landscaping
Area × depth, converted to cubic yards, bag counts, or rolls — with bagged versus bulk buying priced from your own supplier.
Landscaping calculatorsGravel Calculator
Estimate gravel or crushed stone for driveways, paths, and beds — volume, optional weight, and cost from your own prices.
Open calculatorMulch Calculator
Estimate mulch for garden beds and tree rings — bags or bulk, volume in cubic feet, yards, and metres, cost from your own prices.
Open calculatorTopsoil Calculator
Estimate topsoil for lawns, beds, and filling low spots — bags or bulk delivery, volume in cubic feet, yards, and metres, cost from your own prices.
Open calculatorSod Calculator
Estimate sod for new lawns — rectangles, circles, or multiple areas, whole rolls or pallets, priced from your own supplier quotes.
Open calculatorCompost Calculator
Estimate compost for beds, lawns, and tree rings — bags or bulk delivery, volume in cubic feet, yards, and metres, cost from your own prices.
Open calculatorStructure
Concrete & roofing
Volume for pours and surface area for slopes, where the numbers come from shape, depth, and pitch rather than a room.
Exterior calculatorsConcrete Calculator
Calculate concrete volume for slabs and circular pads, in bags or ready-mix, with a waste allowance.
Open calculatorRoofing Calculator
Estimate roofing materials plane by plane — footprint × pitch factor, waste allowance, and whole units from your product's coverage.
Open calculatorCategories
Browse by project
Each project hub groups its calculator with measurement tips and the guides that go with it.
How it works
Three steps from tape measure to shopping list
Enter your measurements
Room sizes, wall height, slab shape — whatever the project needs. Switch between US and metric units at any time.
Calculate material requirements
Use the coverage or yield from your actual product, and set a waste allowance for cuts, mistakes, and cleanup.
Get your shopping list
See the required quantity rounded up to whole containers, boxes, or bags — with an estimated cost if you enter prices.
Method
How the numbers work
A planning tool that shows its work — no sign-ups, no invented pricing, no data collection.
Understand material quantities
See exactly what goes into the number: gross area, openings, coats, and theoretical versus required amounts.
Account for material waste
Add a waste percentage so offcuts, mistakes, and pattern matching do not leave you short mid-project.
Get real purchase quantities
Results round up to whole gallons, boxes, or bags — the way stores actually sell them.
Estimate your material budget
Enter your local prices for an estimated total. No price entered, no cost shown — nothing is invented.
Switch between US and metric
Change the unit system any time; every value converts to the equivalent physical quantity, not just the labels.
Guides
Measurement and buying guides
Practical, step-by-step articles for the measuring and buying decisions behind every project.
Paint
How to Calculate How Much Paint You Need
Measure wall area, deduct openings, multiply by coats, and round up to whole gallons — the complete method with a worked example.
Read the guideFlooring
How to Measure a Room for Flooring
The right way to measure length and width, handle closets and L-shaped rooms, and turn tape-measure numbers into square feet.
Read the guideFlooring
How Much Flooring Should You Buy?
From square footage to sealed boxes: coverage per box, waste by layout, correct rounding, and the case for one spare box.
Read the guideConcrete
How to Calculate Concrete Volume
Slab and round-pad volume in plain steps, with cu ft → cu yd → m³ conversion and two fully worked examples.
Read the guideConcrete
Concrete Bags vs Ready-Mix: How to Estimate What You Need
Where bags stop making sense and trucks take over — yields, job-size rules of thumb, and how to estimate both options.
Read the guideWaste allowance
How Much Extra Material Should You Buy for a Home Project?
What waste actually compensates for, and sensible percentage ranges for paint, flooring, and concrete by project type.
Read the guideMore guides
Questions
Frequently asked
How accurate are material calculators?
They are accurate for planning and budgeting when your measurements and inputs are correct. Real-world variables — surface texture, substrate condition, cutting layouts and installation patterns — always add variance, so treat every result as an estimate, not a construction specification.
Why should I include a waste percentage?
Cutting material to size always produces offcuts, and mistakes, damage, and pattern matching consume extra material. A 5–15% allowance is typical for straightforward projects; complex layouts often need more. Without it you risk running out mid-project.
Can I switch between metric and US units?
Yes. The US / Metric selector at the top converts every value you have entered into the equivalent physical quantity in the other system — dimensions, coverage rates, and prices are all converted, not just relabelled.
How do I calculate the cost of materials?
Enter the price you found at your local supplier per gallon or litre, per box, per bag, or per cubic yard / cubic metre. The calculator multiplies your actual rounded-up purchase quantity by that price. Prices are user-defined; ProjectCalc does not supply or estimate market prices.
Should I order extra materials for irregular projects?
Yes. Diagonal patterns, many corners, angled walls, and irregular room shapes increase offcut waste considerably. For those situations raise the waste percentage above the typical 5–15% range, and keep a spare box or can for future repairs.