How to use the yarn calculator
- Choose a method: pattern yardage → my yarn when substituting, or from a swatch to estimate any project.
- For substitution, enter the number of skeins the pattern calls for and their length.
- For the swatch method, make a swatch in your stitch, weigh and measure it, then enter the finished project size.
- Enter your yarn’s length and weight per skein from the label, and an extra percentage for safety.
The formulas
Substitution: Yardage needed = Pattern skeins × Pattern yards per skein Swatch method: Yarn weight = Swatch weight × (Project area ÷ Swatch area) Yardage = Yarn weight × (Yards per skein ÷ Grams per skein) Skeins = Yardage × (1 + extra) ÷ Yards per skein → round up
Worked examples
- Substitution: 8 skeins × 220 yd = 1,760 yd. Your yarn has 198 yd per skein: 1,760 ÷ 198 = 8.9 → 9 skeins, or 10 with 10% extra.
- Blanket from a swatch: a 6 × 6 in swatch weighs 10 g. A 50 × 60 in blanket is 3,000 in², 83.3 times the swatch, so it needs about 833 g — 9 skeins of 100 g, or 10 with extra.
Yarn weights at a glance
| Number | Name | Typical yd per 100 g | Common uses |
|---|---|---|---|
| 1 | Super fine / fingering | 350–450 | Socks, shawls, baby items |
| 2 | Fine / sport | 300–350 | Light sweaters, baby blankets |
| 3 | Light / DK | 220–260 | Sweaters, hats, amigurumi |
| 4 | Medium / worsted, aran | 170–220 | Blankets, sweaters, scarves |
| 5 | Bulky / chunky | 100–150 | Quick blankets, hats, cowls |
| 6 | Super bulky | 50–100 | Chunky throws, arm knitting |
Ranges are typical; always use the length on your own yarn label.
Why the swatch method works
Every stitch pattern uses a different amount of yarn: bobbles, cables and dense crochet stitches eat yarn, while lace and open stitches use far less. Weighing a swatch made in the exact stitch, yarn and hook or needle size captures all of that. Make the swatch at least 4–6 inches square, include a few rows of any border pattern if you can, and block or wash it the way you will finish the project.
Tips
- Buy one dye lot and keep the labels — the dye-lot number is printed on each one.
- Borders and fringe add more; add 10–20% for a wide border or tassels.
- Gauge matters: if your stitches are looser than the pattern’s gauge, you will use more yarn.
- Weigh as you go: weigh the remaining yarn halfway through the project to check your estimate while the shop still has your dye lot.
If you have leftover partial skeins, weigh them and subtract their grams from the total before buying more.
Leftover yarn is never wasted: scraps make granny squares, stripes, pompoms, toys and test swatches for your next project.