Yarn estimator
Weigh a gauge swatch, enter the size of your project and the details on the ball band, and the estimator returns the yarn you need and how many balls to buy.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Knit a swatch in your stitch pattern, wash it, measure it and weigh it on a kitchen scale.
- Enter the swatch size and weight, then the finished project size.
- Enter the ball weight and length from the label.
How it works
Grams = project area ÷ swatch area × swatch weight × (1 + margin). Length = grams ÷ ball weight × ball length. Balls = grams ÷ ball weight, rounded up.
Worked example
A swatch of 10 × 10 cm weighs 5 g. A 50 × 60 cm blanket is 30 swatches, so 150 g; with 10% margin, 165 g. With 100 g balls of 180 m that is 2 balls, and 165 ÷ 100 × 180 = 297 m of yarn.
Tips
- Weigh swatches on a scale with 0.1 g precision; a 1 g error in a 5 g swatch is a 20% error.
- Buy one extra ball if the yarn is hard to find again.
Frequently asked questions
How does it work without a pattern?
It scales the weight of a swatch by area. The swatch represents the fabric, so a project 30 times its area uses about 30 times its yarn.
Why a safety margin?
Seams, edges, shaping and tension differences use extra yarn. 10% is a common allowance; use more for lace or colour work.
Where do I find the ball weight and length?
On the ball band. It lists grams and metres or yards. Use the same dye lot for all balls, which is why it is worth buying them together.
Is it accurate for shaped garments?
It is an estimate based on a flat rectangle of fabric. Sleeves, necklines and cables change it, so treat it as a plan, not a promise.