Calculators that give you
a straight answer.
35 free tools for sizing, mixing, measuring and pricing — from generators and mulch to epoxy, dog food and brisket. Tell the goose what you have, get a number you can act on, plus the formula behind it.
Six categories, 35 calculators
Everything runs entirely in your browser. Nothing you type is sent anywhere.
- Power & Off-Grid Solar, batteries, cable sizing, UPS runtime and EV charging. 4 calculators →
- Generators Generator sizing, cost, fuel, watts, kVA and household load. 6 calculators →
- Maker & Craft Resin, candles, soap, 3D printing, yarn, fabric and pricing. 7 calculators →
- Home & Yard Mulch, pavers, wallpaper, paint, decking, fencing and grass seed. 7 calculators →
- Pets & Animals Dog food portions, cat calories, chicken flocks and aquariums. 4 calculators →
- Everyday Life Pool chemicals, sourdough, coffee, barbecue, parties, tips and rates. 7 calculators →
Popular right now
- Generator Size Calculator Size it from your appliances, or from your floor area and panel — with the surge load included. Open calculator →
- Mulch Calculator Cubic yards, bags or tons of mulch, soil or gravel for any number of beds. Open calculator →
- Epoxy Resin Calculator Work out how much resin a mould, river table or tumbler actually takes, split by part A and B. Open calculator →
- Raw Dog Food Calculator Daily raw food portions by body weight or calories, with monthly quantity and cost. Open calculator →
- Paint Calculator Gallons of paint for a room, with coats, doors, windows and ceiling accounted for. Open calculator →
- BBQ Calculator How much meat to buy for a cookout, adjusted for kids, appetite and sides. Open calculator →
The math is on the page
Every calculator shows the formula it actually runs, worked through with a real example. If the code and the copy ever disagreed, that would be a bug.
Assumptions are listed, not hidden
Densities, efficiency factors, safety margins, rounding — all spelled out, because a number without its assumptions is a guess with decimal places.
Built for the US and Europe
A region switch at the top of every calculator swaps between inches, pounds and gallons and centimetres, kilograms and litres.
Nothing leaves your browser
No accounts, no saved data, no ad trackers. The calculators are plain JavaScript running on your own device.