Metrics Calculator

Construction Calculators

Concrete, paint, gravel, and building material calculators for contractors, DIYers, and homeowners. Enter your project dimensions and get instant material estimates.

Enter your project dimensions and get a full materials list with quantities and estimated cost. Each calculator accounts for waste, standard product sizes, and real-world factors like door and window cutouts. All 10 tools include cost estimation so you can budget before you buy.

10 calculators available

Which calculator do you need?

For foundation and flatwork projects, the concrete calculator handles slabs, footings, columns, and tube fills. It gives you cubic yards and the number of bags (60 lb, 80 lb, or 90 lb) with a built-in waste factor. For roof replacements, the roofing calculator converts your roof dimensions into squares, shingle bundles, underlayment rolls, and a full materials list.

Interior projects have their own tools. The drywall calculator counts sheets, screws, tape, and joint compound for any room, deducting doors and windows automatically. The paint calculator works the same way, giving you gallons needed per coat with coverage rates for different paint types.

Common questions about construction estimates

How do I calculate concrete in cubic yards?

Multiply length x width x depth (all in feet), then divide by 27 (since there are 27 cubic feet in a cubic yard). A 20 ft x 10 ft slab that's 4 inches thick would be 20 x 10 x 0.333 = 66.6 cubic feet, divided by 27 = 2.47 cubic yards. Always add 5-10% for waste, spillage, and uneven subgrade. The concrete calculator handles the unit conversions and waste factor for you.

How much waste should I plan for?

It depends on the material. For drywall and plywood, plan for 10% waste on simple rectangular rooms and 15% if you have many cutouts or odd angles. Flooring waste runs 5-10% for straight-lay patterns and 15-20% for diagonal or herringbone layouts. Concrete typically needs 5-10% extra, and roofing shingles require about 10-15% for waste and starter/cap shingles. Our calculators let you set the waste percentage, and most default to the industry-standard recommendation for that material.

How many gallons of paint do I need for a room?

One gallon of paint covers about 350-400 square feet per coat. Measure the total wall area (perimeter x ceiling height), then subtract about 20 sq ft per door and 15 sq ft per window. A 12 x 14 ft room with 8 ft ceilings has 416 sq ft of wall area; subtract two doors and two windows (about 70 sq ft) and you're left with 346 sq ft, which is one gallon per coat or two gallons for the standard two coats. The paint calculator handles the deductions and rounding for you.