Construction and Home Calculators
These calculators turn measurements into shopping lists for building and home-improvement jobs: how much concrete a slab or footing needs and how many bags that is, how many tiles and boxes cover a floor, how many squares and bundles of shingles a roof takes, how many cubic yards or tons of gravel and mulch a bed needs, how to lay out a staircase, how many BTUs a room needs and what an appliance costs to run.
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All Construction & Home (8)
Concrete Calculator
Concrete volume and bags for slabs, footings, columns and stepsSquare Footage Calculator
Square footage of rooms and irregular areas, with cost estimatesTile Calculator
Number of tiles and boxes for a floor or wall, with wasteRoofing Calculator
Roof area, pitch factor, squares and shingle bundlesGravel and Mulch Calculator
Cubic yards and tons of gravel, mulch, soil or sand for an areaStair Calculator
Riser height, tread depth and stringer length for a staircaseBTU Calculator
Heating or cooling BTUs needed for a roomElectricity Cost Calculator
Running cost of an appliance from watts, hours and price per kWh
Which tool do I need?
Buy the right number of concrete bags for a slab
Enter the slab size and thickness to get the volume and the count of 40, 60 or 80 lb bags with extra for waste.
Estimate flooring or tile for a room
Measure the room in sections for the total area, then work out tiles and boxes with the waste you expect from cuts.
Order shingles for a reroof
Enter the footprint and pitch to get the true roof area, the number of squares and the bundles to buy.
Size an air conditioner or heater for a room
Enter the room size, ceiling height and conditions to get the BTUs needed, then check what it will cost to run.
About Construction & Home
Each one works in imperial or metric units and adds a waste allowance you can change, because cuts, breakage and uneven ground always use more material than the bare geometry. The Square Footage Calculator handles irregular rooms by adding up rectangles and other shapes and can price the result per square foot.
Treat the numbers as planning estimates. Material yields, bag sizes and densities vary by product, local building codes set the limits for stair rise and run, and heating and cooling loads depend on insulation and climate as well as floor area. Check product data and local rules, or ask a professional, before ordering or building.
Guides
- Estimating Concrete, Flooring, Tile and Gravel Without Running ShortHow to turn measurements into cubic yards, square feet, boxes and tons: the unit traps, bag yields, waste allowances and densities that decide what you actually order.
- Roof Pitch, Stair Layout, AC Sizing and Running Costs ExplainedThe geometry behind roof squares and stair stringers, the IRC numbers a stair has to meet, how the ENERGY STAR chart sizes an air conditioner, and how watts become a bill.
Frequently asked questions
How much extra material should I add for waste?
A common starting point is 5 to 10% for concrete and straight flooring and 10 to 15% for diagonal tile or complex rooms. Each calculator lets you set the percentage.
How many bags of concrete make a cubic yard?
About 45 bags of 80 lb premix or 60 of 60 lb, since an 80 lb bag yields roughly 0.6 cubic feet. Check the yield printed on the brand you buy.
Why do roofers order shingles in squares?
A square is 100 square feet of roof surface. Most asphalt shingles come three bundles to a square, but check the coverage on the wrapper.
Do these calculators follow building codes?
They use common code limits as defaults, such as the maximum stair riser height, but codes differ by country and town. Confirm with your local building department.