Leather Hard: Pottery Calc

Make the mug you meant to make, and know what the one you just threw will hold.

Leather Hard works both ways at the wheel.

MAKE TO VOLUME
Choose the piece, the capacity you want after firing, the wall profile and your clay's shrinkage. Get the wet inside measures to aim for: rim diameter, inside height, base diameter and headspace, in centimetres.
• Espresso, cup, mug, tumbler, bowl or pitcher
• Suggested capacities, or type your own from 30 to 5,000 ml
• Straight, tapered or rounded profile
• A to-scale drawing that updates as you go

MEASURE A PIECE
Already thrown? Enter the inside measures of the wet piece and see how much it will hold after firing, up to the fill line and full to the rim.
• Works with the same profiles and shrinkage
• One tap carries the suggested measures over, so you only correct what came out different

MADE FOR THE WHEEL
• Inside measures, taken while the clay is still wet
• A visual guide shows where to take each measure
• Accounts for shrinkage in all three dimensions and the space left below the rim
• Clear about its assumptions and margin of error

SIMPLE AND PRIVATE
• No account and no ads
• Works offline
• English and Portuguese, switchable in the app

The measures are geometric estimates for round, symmetrical pieces. Uneven walls, warping and your clay's real shrinkage can change the result, so test with your own clay.