Home & DIY

Calculate how many gallons or litres a pool, hot tub or aquarium holds — rectangular, round or oval, with shallow and deep ends.

Work out how much chlorine (liquid, cal-hypo or trichlor) raises free chlorine by a target amount, and how much shock you need for your pool's volume.

Estimate the energy and cost to heat a pool or hot tub by a number of degrees with a gas heater, electric heater or heat pump.

Work out how much grass seed or fertilizer your lawn needs from its area — for new lawns or overseeding — and how much nitrogen a fertilizer bag supplies.

Find out how much an appliance costs to run per day, month and year from its wattage, hours of use and your electricity rate.

Calculate the area of rooms, plots and surfaces — rectangles, circles, triangles and trapezoids — in square feet, square metres, square yards and acres, with material cost.

Find the best TV size for your seating distance — or the ideal distance for your TV — using the SMPTE (30°) and THX (40°) viewing angle guidelines.

Work out curtain width and length for a window — rod width, fullness and drop — so curtains hang properly whether closed or open.

Compare mattress sizes across the US, UK and Europe — twin, full, queen, king, super king — in inches and centimetres, with suggested rug sizes for each bed.

Check whether a sofa, fridge or other furniture will fit through a doorway or hallway — including tilting it on its side or at an angle.

Size appliances for a room: dehumidifier capacity (pints/day), air purifier CADR for its square footage, and the lumens of light the room needs.

Size a tank water heater by peak-hour hot water demand (first-hour rating), or a tankless heater by flow rate and temperature rise.

Compare annual heating costs of a heat pump with a gas, oil, propane or electric furnace from your heat demand, fuel prices and efficiencies.

Estimate household water use from showers, toilet flushes, laundry and dishwashing — and the monthly cost at your water and sewer rates.

Estimate your home's electrical load and the service panel size (amps) it needs, using a simplified version of the NEC standard method.

Estimate how many moving boxes you need by home size and packing style, and the storage unit size that fits your belongings.

Estimate the weight of snow on a roof from depth and snow type — pounds per square foot and total load — and compare it with the roof's design load.

Plan a renovation budget room by room — list the line items, add a contingency, and see the total and the share each part takes.

Calculate concrete for a slab, footing or round column in cubic yards and cubic metres — and how many 40, 60 or 80 lb bags you need.

Estimate how much paint you need for a room's walls (and ceiling) in gallons or litres, allowing for doors, windows and the number of coats.

Work out how much flooring, carpet or countertop material you need — square feet with waste, boxes of flooring, square yards of carpet and the total cost.

Calculate how many tiles you need for a floor or wall — including grout joints and waste — plus an estimate of grout bags.

Estimate drywall sheets and screws for a room's walls and ceiling — or rolls of wallpaper — allowing for doors, windows and waste.

Calculate roof area from the house footprint and roof pitch, then the roofing squares, shingle bundles, underlayment rolls and cost.

Calculate how many cubic yards (or bags) of mulch, topsoil, gravel or sand you need for an area and depth — plus the weight in tons.

Estimate fence posts, panels or pickets, rails and concrete for a fence line — and the material cost.

Estimate decking boards, joists, screws and stain for a rectangular deck — with board width, gap and joist spacing options.

Calculate board feet for hardwood and lumber from thickness, width, length and quantity — and the cost at a price per board foot.

Design a staircase from the total rise: number of steps, riser height, tread depth, total run, stringer length and angle — checked against the IRC code limits.

Estimate bricks, concrete blocks or retaining wall blocks for a wall of any size — with openings, mortar joints and waste.

Find the recommended attic insulation R-value for your climate zone and how many inches of fiberglass, cellulose or spray foam it takes to get there.

Metric (M2–M24) and UNC (#4–3/4") thread chart with pitch, threads per inch, tap drill and clearance hole sizes — plus a tap drill calculator for any thread.

Make a printable house cleaning schedule — daily, weekly, monthly and seasonal chores, spread across the week and shared between household members.

Find the right desk, chair, standing-desk and monitor height for your body — for a comfortable, healthier home office setup.