Maker & Craft Calculators
Craft projects fail at the shopping stage more often than at the workbench. These seven calculators work out how much material a project actually needs, and what it costs to make — so you buy once and price properly.
- Epoxy Resin Calculator Work out how much resin a mould, river table or tumbler actually takes, split by part A and B. Open calculator →
- Candle Making Calculator How much wax and fragrance oil a batch of candles needs, plus a wick size for your jar. Open calculator →
- Soap Lye Calculator Work out exactly how much lye and water your oils need, with superfat and a full safety brief. Open calculator →
- 3D Print Cost Calculator The real cost of a print — filament, power, wear and failures — and what to charge for it. Open calculator →
- Yarn Calculator How much yarn a blanket, scarf or hat takes — by craft, stitch density and yarn weight. Open calculator →
- Fabric Calculator How much fabric a project needs, with hems, seams and pattern repeat already added. Open calculator →
- Vinyl & Sticker Pricing Calculator What to charge for decals, shirts and signs once materials, labour and marketplace fees are in. Open calculator →
About these maker & craft calculators
Every craft has its own arithmetic and most of it is volume or weight hiding behind a shape. Resin is a volume problem: work out the cubic capacity of the mould, convert to millilitres, split by the mix ratio. Candles are the same problem with a density step, because wax is sold by weight and poured by volume. Soap is a chemistry problem with a published constant per oil. Yarn and fabric are area problems with a fudge factor for how tightly you work.
The recurring mistake is buying to the exact calculated figure. Resin clings to mixing cups, fabric shrinks and needs squaring, yarn dye lots differ between orders, and a print fails at hour nine. Every calculator here adds a waste margin you can see and change, rather than burying it. Where a number is genuinely a rule of thumb — yarn yardage per square foot, wick size by jar diameter — it is labelled as one in the assumptions rather than dressed up as precision.
Three of these are pricing tools as much as material tools. If you sell what you make, the cost that matters is not the filament or the vinyl: it is the filament plus the electricity plus the failure rate plus the marketplace fee plus your own time. The 3D printing and vinyl calculators build that full picture and work backwards to a price that leaves the margin you asked for. Most hobby sellers undercharge because they price the material and give away the labour.
The soap calculator carries a safety section for a reason. Sodium hydroxide is caustic enough to cause serious burns and it heats violently on contact with water. The maths here is standard saponification arithmetic and it is reliable, but it assumes you are handling lye properly: goggles, gloves, ventilation, and lye into water rather than the other way round.
Other calculator clusters
- Power & Off-Grid Calculators Solar, batteries, cable sizing, UPS runtime and EV charging.
- Generator & Backup Power Calculators Generator sizing, cost, fuel, watts, kVA and household load.
- Home & Yard Calculators Mulch, pavers, wallpaper, paint, decking, fencing and grass seed.
- Pets & Animals Calculators Dog food portions, cat calories, chicken flocks and aquariums.
- Everyday Life Calculators Pool chemicals, sourdough, coffee, barbecue, parties, tips and rates.