Free Home Improvement Calculators
Stop guessing and start measuring. Enter your room or project dimensions and instantly find out exactly how much paint, flooring, concrete, tile, mulch or lumber to buy — plus what it will cost. Every calculator is free, runs right in your browser, and takes less than a minute.
Painting & Finishing
Wall area minus doors and windows, number of coats, and gallons to buy — including cost per gallon.
How much grout your tile job needs, based on tile size, joint width and depth.
Floors & Walls
Laminate, vinyl or hardwood: total square footage with waste allowance, boxes to buy and total cost.
How many tiles you need for any floor or wall, with waste allowance for cuts and breakage.
Sheets of drywall for walls and ceilings, plus an estimate of screws.
How many bricks you need for a wall, including mortar joints and waste allowance.
Outdoors & Structure
40, 60 or 80 lb bags for slabs, footings and post holes, with cubic yards shown.
How much mulch or gravel to order: bags, cubic yards or tons for any bed or patio.
How many deck boards and fasteners you need for a new or resurfaced deck.
How many fence posts, pickets, rails and bags of concrete for any fence run.
Woodworking & Carpentry
Board feet and total cost for any lumber order, with support for multiple board sizes.
Code-compliant number of steps, actual riser height, total run and stringer length.
Why Use These Calculators?
Home improvement stores accept returns, but a wrong material estimate still costs you a second trip, wasted time and wasted money. Buying 30% too much flooring or concrete can add hundreds of dollars to a small project. Our calculators use the same formulas contractors use — wall area minus openings, waste allowances for cuts and breakage, and coverage rates from real product specifications — so you buy the right amount the first time.
Each calculator explains the math in plain English, walks through a complete worked example, and answers the questions DIYers ask most. Every result includes a suggested waste allowance and rounds up to whole containers, because you cannot buy 1.9 gallons of paint.