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Measure once.
Buy the right amount.

22 fast calculators — rug size, square footage, paint, tile, concrete and more — every one showing its formula, plus 70+ step-by-step guides. No sign-up, nothing stored.

22 calculators 70+ guides 100% free & ad-supported
Two people measuring a living-room floor with a tape measure
Shows the mathevery tool reveals its formula & worked example
US unitsfeet, inches, gallons & common sheet sizes
No sign-upnothing stored, works instantly
70+ guidesstep-by-step how-tos for every project
Worker smoothing a freshly poured concrete slab on a driveway
Real projects, real math

Measure the project once — order the exact amount, every time.

From a concrete driveway to a wood deck, every calculator shows its formula and a worked example. Skip the guesswork and the extra trips.

Most-used calculators

All 22 tools →
Size & area
Material quantities
Structure & install
Heating & cooling

Why the numbers matter before you buy

Most home-material mistakes aren't about taste — they're about math. A rug a few inches too small under a king bed leaves an awkward gap; one gallon of paint too little means a second trip and a visible seam; a few bags of concrete short at the end of a pour is the last thing you want.

Every tool shows its formula and a worked example, so the number isn't a black box. Measure twice, add 10% for waste, and verify with your supplier — start with a calculator, then check the matching guide for the full method.

A modern living room with a large beige area rug under the sofa and coffee table
Painting a bedroom wall with a roller
Painting — count walls, ceiling & trim separately.
Laying grey tile on a kitchen floor
Tiling — allow for cuts & 10% waste.
Installing hardwood flooring with a mallet
Flooring — add waste for cuts & off-cuts.
New wooden fence in a sunny garden
Fence — count posts, rails & pickets.

Popular guides

All guides →

Rug size by bed

King, queen, full, twin — exact rug sizes and placement for every bed type.

Read the guide →

How to measure for a rug

A simple 6-step method to measure any room and pick a rug that fits.

Read the guide →

How much paint do I need?

Room-by-room gallons chart, the coverage formula, and common mistakes.

Read the guide →

How much concrete for a slab?

Cubic yards to bags, depth by use, and a worked example.

Read the guide →

Square footage of a house

How to calculate any room or whole house, and what counts in a listing.

Read the guide →

See all guides

Carpet vs hardwood, shingles, fence cost, and more how-to articles.

Browse all guides →

Ready to buy without over-ordering?

Free, no sign-up, US units. Pick a calculator, get the exact amount, and check the guide before you spend.

Start with a calculator