Math and measurements, made simple

From fractions to calculus, plus tools that solve real problems on the job and at home. No confusion.

17 free tools · no sign-up · works on your phone

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Step-by-step lessons to brush up on math: fractions, algebra, geometry, and more.

Calculators that do the math for you: concrete, measurements, conversions, and more.

Yards and bags for slabs, footings, walls, columns, and stairs.

How many gallons to cover your walls, by room size and coats.

How many boxes of tile, laminate, or vinyl by room area.

Steps, riser, tread, stringer length, angle, and concrete volume — with a diagram and code check.

Add, subtract, simplify, multiply, divide, and convert to decimals.

Order of operations, negatives, variables, and solving equations.

Limits, derivatives, and integrals explained in plain English.