Free Online Calculators
32 calculators and converters for home projects, seller fees, pools, gaming, work hours and more. No accounts, no tracking, nothing to install.
Home & yard (12)
- deck material calculator
— boards, screws or clips, and cost from deck size, board width and waste factor.
- gravel calculator
— cubic yards, tons and cost from area and depth, by stone type.
- mulch calculator
— cubic yards, bag count, and bag-versus-bulk cost for any bed.
- concrete bag calculator
— how many 80, 60 or 40 lb bags for a slab or post holes.
- raised bed soil calculator
— soil volume, bag count and a mix-recipe splitter for garden beds.
- tile calculator
— tile and box counts with waste percent and cost per box.
- drywall calculator
— sheets plus mud, tape and screws for any room, doors and windows deducted.
- fence calculator
— pickets, posts, rails and post-hole concrete for a whole run.
- paint calculator
— gallons per coat with doors and windows deducted from the wall area.
- roof shingle calculator
— true roof area from pitch, in squares and bundles, waste included.
- paver calculator
— paver count by size plus polymeric sand bags and gravel base.
- board foot calculator
— hardwood board feet with the trade's quarter-size and round-up rules.
Fees & seller money (4)
- stripe fee calculator
— fee and net on any charge, or the charge that nets a target amount. US and Canada rates.
- paypal fee calculator
— Goods & Services fee and net both directions, card-funded and international.
- etsy fee calculator
— listing, transaction, processing and offsite-ads fees per sale, 2026 rates.
- mercari fee calculator
— the 10% selling fee and your payout, current and pre-2025 structures.
Pool care (3)
- pool salt calculator
— pounds and bags of salt to add to reach your target ppm.
- pool bleach calculator
— liquid chlorine dosing by strength percentage, in gallons, ounces or liters.
- pool volume calculator
— gallons, liters and water weight for rectangular, round and oval pools.
Gaming (3)
- twitch bits to usd
— what bits are worth both directions, plus the cheapest pack combination to buy.
- edpi calculator
— DPI × sensitivity with cm per 360 for CS2, Valorant, Overwatch 2 and more.
- sensitivity converter
— carry the same aim between games: cm-per-360 math, any pair of titles.
Work & time (3)
- timecard calculator
— weekly hours from daily in/out times minus unpaid lunch, with overtime pay.
- minutes to decimal hours converter
— h:mm to decimal and back, with a conversion chart.
- prorated rent calculator
— daily rate by move-in day under both the actual-days and 30-day methods.
Garage (2)
- tire size calculator
— compare two markings like 225/65R17 vs 235/65R17: diameter, width, speedo error.
- nm to ft-lbs converter
— torque in newton-meters, foot-pounds, inch-pounds and kgf·m in one box.
Craft & home brew (3)
- epoxy resin calculator
— gallons from area × thickness, split by mix ratio (1:1, 2:1, anything).
- candle wax calculator
— wax weight by container count, pour fill and fragrance load.
- abv calculator
— alcohol by volume from original and final gravity, both standard formulas.
Canadian tax (1)
- reverse HST calculator
— pull HST or GST out of a receipt total: Ontario and every province's rate.
Pets (1)
- dog food calculator
— daily calories and cups from your dog's weight and activity level.
Reference
- formula library
— every formula on this site with its worked example and its sources, 32 tools in one page.
- how these calculators are built and checked
— the build pipeline, the 140 known-answer checks, and the DOM test that clicks every button.
Notes
Every calculator states its formula, works one example with numbers you can check on paper, and lists its sources with a review date. Wherever a fee, rate or material figure can drift, it is an editable input on the page. All calculations run in your browser; nothing you type is sent anywhere.
Last reviewed: October 2026.