How to use the yarn yardage calculator
- Choose inches or centimeters and use the same unit for every size.
- Enter the project width and length and the number of pieces, such as 2 for a front and a back of the same size.
- Knit or crochet a swatch, then enter its width, its height and the yards of yarn it used.
- Set an extra percent for seams and mistakes, and the yards per skein from the label. Read the yards, the meters and the number of skeins to buy.
Formula
Yarn per square unit = swatch yards / (swatch width x swatch height)
Project area = width x length x pieces
Yards = project area x yarn per square unit
Yards with extra = yards x (1 + extra percent / 100)
Skeins = yards with extra / yards per skein, rounded up
Meters are yards x 0.9144. Everything scales your own swatch, so no yardage per garment is assumed.
A 40 by 50 inch blanket
A swatch of 4 by 4 inches used 12 yards of yarn, which is 0.75 yards per square inch. The blanket is 40 by 50 inches, so its area is 2,000 square inches and it needs 1,500 yards. With 10% extra the figure is 1,650 yards, which is 1,508.8 meters.
At 200 yards per skein that is 8.25 skeins, rounded up to 9 skeins. Nine skeins hold 1,800 yards, so 150 yards would be left over.
Why a swatch works better than a rule of thumb
The amount of yarn in a square inch depends on the yarn, the hook or needles, the stitch pattern and how tightly you work. Your own swatch captures all of that. The tool then scales it by area. It claims nothing about how much yarn a sweater or a hat usually takes, because that depends on size and design.
Measure the swatch after washing and blocking if you will wash the finished piece, and use the yarn the swatch actually used. If you weigh the swatch, convert its weight to yards using the length and weight on the yarn label.
Where the estimate falls short
The estimate assumes one stitch pattern and one gauge across the whole piece. Cables, lace, textured stitches, color work, edgings and shaping change the yarn used. If the project has several patterns, swatch each and add the results. See the knitting gauge calculator for stitch counts, and the fabric yardage calculator when you move to sewing.
The extra percent and the yards per skein are example values. Buy all your skeins from the same dye lot when you can.
Assumptions and limits
- The whole project uses the same stitch pattern at the same gauge as the swatch.
- Extra yarn (10%) and yards per skein (200) are example values you replace.
- Sizes are flat finished measurements in one unit.
- No typical yardage for any garment or yarn weight is assumed.
Frequently asked questions
How do I work out how much yarn I need?
Measure how much yarn a finished swatch uses, divide by its area, and multiply by the area of your project. Add a little extra, then divide by the yards in one skein and round up.
Do I use the same unit for the swatch and the project?
Yes. The tool divides yards by an area in one unit and multiplies by an area in the same unit, so mixing inches and centimeters gives a wrong answer.
How much extra yarn should I add?
The 10% is only an example. Add more for seams, a gauge you are unsure of, or a pattern you may need to redo, and less when you have a spare skein.
Why is the leftover yardage shown?
Skeins are bought whole, so the last skein is rarely used up. The leftover tells you how much margin you have if the estimate is a little low.