Kilnshrink

Kilnshrink is a pottery shrinkage calculator for ceramicists. Clay loses size during drying and again during firing, and every clay body shrinks a different percentage. If you want your finished mug to hold 12 ounces or your finished bowl to measure six inches across, you have to throw it slightly larger to begin with. Kilnshrink does that math. WHAT KILNSHRINK DOES - Reverse calculation, the main workflow: tell Kilnshrink the size you want the finished piece to be, and it returns the size to throw it wet. The classic "I want a six inch bowl" problem, solved in one tap. - Forward calculation: tell Kilnshrink the size you are about to throw, and it returns the size the piece will be after firing. Useful for catching a project before it goes in the kiln, or for sizing a handle before you attach it. - Eighteen built-in clay presets covering the most common studio choices: stoneware, porcelain, earthenware, raku, paper clay, and air-dry. Each preset stores its name, family, cone temperature, and shrinkage percentage drawn from published manufacturer data and the standard pottery literature. - Custom clay entries. Test-fire a 100 mm bar of your own clay body, measure the shrinkage, and add it to your library. Custom entries can be deleted any time. - Single, two, or three dimension modes. Single covers most pots. Two helps when you care about diameter and height. Three is for boxes, slabs, lids, and any project where every axis matters. - Inches with friendly fraction parsing. Type three and a quarter as "3 1/4". Type three and three eighths as "3 3/8". Type plain decimals if you prefer. Output rounds to the nearest sixteenth of an inch. - Centimeters with one-place precision. Slide between units in Settings. - A clear before-and-after bar diagram on every result, so you can see at a glance how much your clay is shrinking. - Project history. Save any calculation with a project name and optional notes. The list holds up to fifty projects locally. Swipe to delete, tap to see the full detail. - Default clay. Pick the clay you use most often and Kilnshrink keeps it selected across launches. THE FIRING CHAIN A two screen onboarding walks you through the standard pottery chain. Wet. Leather hard. Bone dry. Bisque. Glaze. Each step pulls a little more water and a little more size. Most clay bodies lose eight to fifteen percent of every linear dimension between wet and final fire. PRIVATE BY DESIGN Kilnshrink has no account, no ads, no analytics, no tracking, no subscription, and no developer backend. Saved projects and your clay preference live in this app's local storage and do not leave your device. The app does not request camera, microphone, contacts, calendar, photos, location, or notifications. WHO IT IS FOR Potters working at the wheel or with handbuilt forms. Ceramic students learning to size for shrinkage. Studio teachers who want a simple tool to hand a beginner. Anyone tired of a fourteen dollar physical shrinkage ruler. Kilnshrink is a one-time paid utility. No subscription, no in-app purchases. Buy it once, keep it forever.