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Clay Shrinkage Calculator

Wet-to-fired size, the wet size needed for a target fired size, or the shrinkage rate from two measurements.

Related tools

All Crafts & making tools →
Beading Pattern CalculatorTotal beads and finished size for a loom or peyote pattern from rows, columns and bead size.Candle Wax CalculatorTurn a container's volume into the wax weight and fragrance oil you actually need, for soy, paraffin, coconut, beeswax, palm or a blend — in oz, grams and pounds.Crochet Hook Size ConverterConvert crochet hook sizes between metric (mm), US and UK, with a full reference table.Cross-Stitch Floss CalculatorEstimate how many skeins of floss a design needs from stitch count, strands and fabric count.Cross-Stitch Size CalculatorFinished design size from stitch count and fabric count, in inches and cm, with an optional margin.Embroidery Thread Length CalculatorEstimate embroidery thread length from stitch count, average stitch length and a waste allowance.Fabric Yardage CalculatorHow much fabric to cut a number of pieces from a bolt of a given width — in meters and yards.Knitting Needle Size ConverterConvert knitting needle sizes between metric (mm), US and UK, with a full reference table.

Clay Shrinkage Calculator is free to use as often as you like, directly from this page. You will find it under Crafts & making, with Beading Pattern Calculator and Candle Wax Calculator for the neighbouring cases.

How to use it

  1. Open the tool — no signup or install needed.
  2. Enter your input or adjust the available options.
  3. Get your result instantly, then copy or download it.

Frequently asked questions

What does Clay Shrinkage Calculator do?

Wet-to-fired size, the wet size needed for a target fired size, or the shrinkage rate from two measurements.

When would I actually use this?

Buying the right amount before starting: how many skeins a jumper needs, how much wax fills the moulds you own, how much resin a bezel takes, how much fabric a quilt binding eats.

What is the most common mistake?

Sizing from the pattern's yarn rather than your own. Two yarns sold as the same weight can differ by a fifth in metres per hundred grams, and a hook or needle size converted between systems is a nominal diameter, not a promise about gauge — knit a swatch.

How is Clay Shrinkage Calculator different from Beading Pattern Calculator?

They sit next to each other but answer different questions. Beading Pattern Calculator: total beads and finished size for a loom or peyote pattern from rows, columns and bead size. Pick whichever matches what you're starting from — both are free.

Is there a tool for the next step?

Candle Wax Calculator is the closest one after this: Turn a container's volume into the wax weight and fragrance oil you actually need, for soy, paraffin, coconut, beeswax, palm or a blend — in oz, grams and pounds.

What else is worth having open alongside it?

Crochet Hook Size Converter and Cross-Stitch Floss Calculator — they come up in the same task often enough to be worth a second tab.

Where do the figures come from?

Hook and needle equivalences follow the Craft Yarn Council's metric table; the soap calculator uses published saponification values, which vary by oil batch, so the lye figure is a starting point that a superfat margin is meant to absorb.

Further reading

All guides →
ExplainerClay Shrinkage: Divide, Do Not Add a PercentageTo fire at 25 cm with 12 per cent shrinkage you throw at 28.41 cm, not 28. Adding the percentage instead of dividing by its complement leaves you 3.6 mm short — every time, in the same direction.ExplainerEvery Oil Blend Has Its Own Lye RequirementA thousand grams of olive oil needs 127 g of lye; the same thousand grams of a palm-coconut-olive blend needs 143. Saponification is stoichiometry, not a rule of thumb, and a five per cent error in one direction makes a caustic bar.ExplainerA Jar Is Sold by Volume and Wax Is Bought by WeightThe trade rule of 0.8 oz of wax per fluid ounce of jar is an effective density of 0.767 g/mL — calibrated for soy at an 85 per cent fill. It is right to within 0.2 per cent for soy and under-reads beeswax by six.ExplainerThe Flat Pattern of a Cone Is a Sector, Not a CircleRoll a 50 mm cone 80 mm tall and its pattern is a 190.8° slice of a 94 mm circle. Flatten a nearly cylindrical lampshade and the pattern radius runs to 839 mm — the shallower the taper, the further away the apex.How-toBinding a Quilt: Strips, Bias and the Fabric to BuyA 150 × 200 cm quilt has a 725 cm perimeter once you allow for the join, which is seven strips off a 110 cm bolt and six off a 140 cm one. The strip width you choose sets the fabric, and the corners set whether it lies flat.ExplainerFabric Yardage Is a Staircase, Not a SlopeTwelve pieces of 46 cm take 1.84 m on a 140 cm bolt. Make them 47 cm and it jumps to 2.82 m — fifty-three per cent more fabric for one centimetre, because the third piece no longer fits across.