How much yarn do I need?
Weigh your swatch, enter your project size, and get the number that actually matters: how many skeins to put in the basket. Nothing is uploaded and nothing is stored.
How this is calculated
No lookup tables and no assumptions about your yarn. The whole calculation is four steps of arithmetic on numbers you supply:
- Yarn density. Your swatch weight divided by its area gives grams per square unit — the real consumption rate of your yarn at your tension in your stitch.
- Project area. Width × length × number of pieces.
- Weight needed. Project area × density, then multiplied by your safety margin.
- Skeins. Weight needed divided by skein weight, rounded up — you cannot buy 3.2 skeins. Length is converted using the yards-per-gram printed on your ball band.
Where this is less accurate: heavily textured stitches such as cables pull the fabric in, so a flat swatch under-reports them — swatch in the actual pattern stitch if you can. Garments with a lot of shaping have more edge than a rectangle of the same area, which is what the safety margin is for. And if you do not block your swatch the same way you will block the finished piece, the area you measured is not the area you will end up with.
Reference: standard yarn weights
Useful if you are substituting one yarn for another — a substitute should knit to a similar gauge, or your fabric and your yardage both change. Gauge is stocking stitch over 4 inches / 10 cm.
| CYC | Name | Knit gauge | Needle | Crochet gauge | Hook |
|---|---|---|---|---|---|
| 0 | Lace | 33–40 sts | 1.5–2.25 mm | 32–42 dc | 1.4–2.25 mm |
| 1 | Super fine | 27–32 sts | 2.25–3.25 mm | 21–32 sts | 2.25–3.5 mm |
| 2 | Fine | 23–26 sts | 3.25–3.75 mm | 16–20 sts | 3.5–4.5 mm |
| 3 | Light / DK | 21–24 sts | 3.75–4.5 mm | 12–17 sts | 4.5–5.5 mm |
| 4 | Medium / worsted | 16–20 sts | 4.5–5.5 mm | 11–14 sts | 5.5–6.5 mm |
| 5 | Bulky | 12–15 sts | 5.5–8 mm | 8–11 sts | 6.5–9 mm |
| 6 | Super bulky | 7–11 sts | 8–12.75 mm | 7–9 sts | 9–15 mm |
| 7 | Jumbo | 6 sts or fewer | 12.75 mm+ | 6 sts or fewer | 15 mm+ |
Gauge ranges from the Craft Yarn Council Standard Yarn Weight System.
Making a blanket?
How much yarn for a blanket has the same calculator with every standard blanket size ready to tap — lovey, crib, throw, twin, queen and king.
Questions people actually ask
Why do I need to weigh a swatch? Can't you just tell me?
Because nobody can. The same 'worsted' yarn from two brands can differ by 30% in how much you need for the same blanket — it depends on your yarn, your needles, your tension and your stitch pattern. Any site that gives you a number without those is guessing. Weighing a swatch takes ten minutes and turns a guess into arithmetic.
How big should the swatch be?
At least 4×4 inches (10×10 cm) of even fabric, measured inside the edges — cast-on and bind-off rows distort the stitches. Bigger is more accurate: an 8×8 inch swatch roughly halves your error. Block it the way you will block the finished piece, because blocking changes the area.
What scale do I need?
A kitchen scale that reads to 0.1 g. A scale that only reads whole grams is fine for large swatches but adds a few percent of error on small ones. If your scale rounds to 1 g, use a bigger swatch.
Why add a safety margin?
Three real reasons: gauge drifts as you relax into a project, seaming and edging eat yarn that is not part of the flat area, and you want enough left to fix a mistake. 15% is the usual working figure. Go to 20% for colourwork or anything with a lot of seaming, and 10% if you are working flat with no shaping.
What is a dye lot and why does it matter?
Yarn is dyed in batches, and two skeins of the same colour from different batches can be visibly different in daylight even when they look identical in the shop. The difference shows up as a stripe across your finished piece. Buy every skein you need in one purchase, from the same lot number, and buy the spare then too — not later.
Does this work for crochet as well as knitting?
Yes. The method does not care how the fabric was made, only what it weighs and how big it is. Crochet generally eats more yarn than knitting for the same area, and this method captures that automatically because you swatched in your own stitch.
Last checked: 2026-08-09