easyonlinecalculator

Home & DIY Calculators

Home and DIY calculators for measuring a space and estimating materials. Find the square footage of a room, work out how much paint the walls need with doors, windows and coats, or how much concrete a slab takes in cubic yards and cubic meters. Each page shows its formula and a worked example. Gravel, fence, tile and roofing estimators work out materials, and flooring and other estimators are planned. Every tool runs in your browser and needs no sign-up.

Last updated November 2, 2026

Featured tools

All Home & DIY calculators

Rooms & Surfaces

Square footage and paint amounts for rooms

Outdoor & Landscape

Gravel, mulch, sod, fences and decks

Building Materials

Concrete, brick, drywall and roofing

Heating & Cooling

Heating and cooling estimates

Frequently asked questions

How do I calculate the square footage of a room?

Use the Square Footage Calculator: enter the length and width of each area and it returns the total in square feet and other units.

How much paint do I need for a room?

Use the Paint Calculator: enter the wall length and height, subtract doors and windows, and set the coats and coverage from your can. It returns gallons or liters, rounded up.

How much concrete, gravel or tile do I need?

Use the Concrete, Gravel or Tile Calculator: enter the size, add a waste allowance, and read the total in cubic yards, tons, or tiles and boxes.

Can I measure a room that is not a rectangle?

Yes. The Square Footage Calculator also adds triangles and circles, so you can split an irregular space into simple shapes and total them.

Do these calculators store my numbers?

No. Every calculation runs in your browser and nothing you enter is saved or uploaded.