Measurement Converters
Craft instructions travel, and they bring their units with them. A pattern written in inches, a yarn label in grams, a recipe in cups, a ring size in letters: these converters translate between them so you can buy, cut and mix with confidence. Every page shows the exact factor it uses, the same value in every other unit at once, and the assumptions behind the numbers.
13 converters across 4 groups
Length
Inches to Centimeters
Convert inches to centimetres and back, with the exact 2.54 cm definition.
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Centimeters to Inches
Convert centimetres to inches and back, for pattern and material sizing.
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Meters to Yards
Convert metres to yards and back. Fabrics and yarn are sold in different units depending on the country.
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Yards to Meters
Convert yards to metres and back, for fabric, yarn and trim.
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Millimeters to Inches
Convert millimetres to inches and back. Useful for needle sizes, wire gauges and small hardware.
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Weight
Grams to Ounces
Convert grams to ounces and back. Yarn, beads and resin are often sold by weight in grams.
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Ounces to Grams
Convert ounces to grams and back, for wax, resin and fibre.
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Kilograms to Pounds
Convert kilograms to pounds and back, for clay, wax and larger material orders.
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Volume and temperature
Liters to Gallons
Convert litres to US and UK gallons, pints and fluid ounces.
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Volume Converter
Convert between millilitres, cups, pints, quarts, litres and gallons.
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Temperature Converter
Convert between Celsius, Fahrenheit and Kelvin, with the craft temperatures you actually need.
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Craft specific sizes
How these conversions work
One factor per unit
Every unit in a table carries the number of base units in one of it. Length is counted in millimetres, weight in grams and volume in millilitres, so converting is a multiplication followed by a division: your value times the factor you are coming from, divided by the factor you are going to. Nothing is rounded in the middle of that, which is why the answers agree with each other whichever direction you travel.
Exact where exact exists
An inch is defined as exactly 25.4 millimetres and a pound as exactly 453.59237 grams, so those conversions are exact rather than approximate. Where a unit is itself approximate, the factor is only as good as the standard behind it, and the page says so.
Temperature is different
Celsius, Fahrenheit and Kelvin do not share a zero point, so a single factor cannot express them. That page uses the real formulas instead: F = C x 9/5 + 32, C = (F - 32) x 5/9, and K = C + 273.15.
Sizes are charts, not sums
Ring sizes and paper sizes are separate standards rather than ratios, and pretending otherwise would invent relationships that do not exist. Those pages are built on the one measurement the systems genuinely share, such as the inside diameter of a ring in millimetres, and print the whole chart so you can read across it yourself.
A word for makers: a conversion is only ever as accurate as the measurement you started with, and small millimetre differences matter at the saw, the needle and the mixing jug. Convert, then check against the material in front of you before you cut or mix. Every page here also states what it assumes, so a figure never arrives without its working.