Home & DIY calculators
Cooking, building, garden and interior calculators — scale a recipe, work out how much material to order, or size something before you buy it. The building tools are the ones worth double-checking: quantities here are net, so add your own allowance for cuts and breakage.
Air Fryer ConverterConvert any oven recipe to air fryer temperature and time, adjusted for food type and basket load.Baker's Percentage CalculatorConvert baker's percentages to ingredient weights, with the flour as the 100% base.Baking Pan Size ConverterConvert a recipe between baking pans by comparing base areas, get the scale ratio and a batter-depth note, and auto-scale your ingredient list.BBQ CalculatorTurns a guest list into a shopping list: raw meat by cut — with the honest cooking yields, 50% for ribs and pulled pork against 75% for steak — buns, sides, drinks and ice, then the fuel, charcoal by the kilo or propane as a share of a bottle, and a cost estimate. Metric and imperial together.Brine calculatorWork out how much salt you need for a brine at a target concentration.Butter ConverterConvert butter between cups, sticks, grams and tablespoons.
Beam Load CalculatorEstimate the maximum moment, deflection, bending stress and demand/capacity ratio of a beam for seven load cases — a preliminary check, not a design.Belt length calculator (pulleys)Find the belt length wrapping two pulleys, for an open (same-direction) or crossed (reversed) drive. Enter both pulley diameters and the centre distance to get the belt length, and add a driver speed to read the driven pulley RPM and the linear belt speed.Board Foot CalculatorWork out board feet from thickness, width and length, with quarter notation, metric entry, 30 wood species, moisture content and price.Bolt Torque CalculatorGet the tightening torque of a metric or UNC bolt from its grade, tensile stress area, target preload and lubrication, in N·m and lb·ft side by side.Brick calculatorEstimate the number of bricks for a wall from its area and brick size.BTU calculator (air conditioning)Estimate the air-conditioner power in BTU and kW needed to cool a room.
Garden (10)
All 10 tools →Compost Calculator (C:N Ratio)Mix greens and browns and get the carbon-to-nitrogen ratio of your pile, with tips to hit the ideal 25–30:1.Fertilizer calculatorEstimate how much fertilizer you need to cover a lawn or garden area.Frost Date CalculatorEstimate the average last spring and first fall frost dates and growing-season length from your USDA zone.Grass seed calculatorHow much seed to sow: each grass type has its own recommended seeding rate per 1,000 sq ft, and overseeding an existing lawn takes about half of a new seeding. Enter the area and get the pounds needed for a new lawn and for overseeding.Lawn Fertilizer CalculatorFind how much lawn fertilizer to spread from your lawn area, nitrogen rate and the bag's N-P-K analysis.Mulch calculatorWork out the volume of mulch and number of bags for a garden bed.
Lux to lumens calculatorConvert a target illuminance in lux into the total light output in lumens a space needs. Lux measures brightness on a surface (lumens per square metre); this tool multiplies your target lux by the floor area and divides by a utilisation factor for real-world losses, then estimates the bulb count.Moving boxes estimatorEstimate how many small, medium and large moving boxes you need from your number of rooms.Room lighting calculatorWork out how much light a room needs and how many bulbs to buy. Pick the room type — it sets the recommended illuminance in lux — enter the dimensions and your bulb's lumen output, and it returns the total lumens required and the number of fixtures, adjusted for tall ceilings.