Two ways to answer “how much yarn do I need?”: a quick estimate by project and yarn weight, or an exact figure from a swatch you weigh. Both turn your yarn requirements into yards, meters, and skeins to buy; skeins times price gives the yarn cost.
Make a swatch in your stitch and yarn, weigh it, and measure it. This method gets within a skein of the truth, because it measures your tension, your stitch, and your yarn together.
You Need About
2,688yards
for a throw in 4 · medium weight yarn
- In meters2,460 m
- Skeins to buy13 skeins · buy 14
- Published range2,250–3,125 yd
- Your yarn use
Buy the extra skein. Leftover yarn becomes a pom-pom; a missing skein from a later dye lot becomes a visible stripe.
The Two Formulas
The quick estimate reads from the yardage table below, the ranges yarn makers publish, scaled to your blanket size when you enter one. The swatch method is arithmetic on your own knitting or crochet:
yards per square inch = (swatch grams ÷ swatch area) × (skein yards ÷ skein grams) · total = yards per square inch × project areaWeigh the swatch rather than unraveling it. A gram scale and the two numbers on the yarn label are all the equipment this takes.
Worked Example
A worsted-weight throw, 50 × 60 in, from a swatch: your 4 × 4 in swatch weighs 8 g, and the label says 100 g = 220 yd.
- Yarn in the swatch: 8 g × (220 ÷ 100) = 17.6 yd over 16 square inches: 1.1 yd per square inch.
- The throw is 50 × 60 = 3,000 square inches: 3,000 × 1.1 = 3,300 yd.
- At 220 yd a skein: 3,300 ÷ 220 = 15, 16 skeins once you buy the spare.
- The published worsted range for an afghan is 2,250–3,125 yd: your swatch says you work denser than average, and that is exactly why the swatch method wins.
Yarn Yardage Chart by Project and Weight
Yards, from Lion Brand’s published guide. Crochet takes roughly a quarter more than these knitting figures.
| Project | 1 Super fine | 2 Fine | 3 Light | 4 Medium | 5 Bulky | 6 Super bulky | 7 Jumbo |
|---|---|---|---|---|---|---|---|
| Hat | 250–325 | 250–325 | 200–250 | 200–225 | 125–200 | 125–150 | 30–60 |
| Scarf | 525–825 | 450–625 | 375–500 | 375–500 | 250–375 | 250–375 | 125–200 |
| Socks (pair) | 350–500 | 300–450 | 275–400 | 275–375 | 250–350 | 200–250 | 175–200 |
| Shawl | 550–850 | 450–700 | 400–625 | 375–550 | 350–500 | 350–475 | 300–400 |
| Adult sweater | 3,375 | 1,750–2,625 | 1,500–2,250 | 1,125–1,625 | 950–1,125 | 825–1,125 | 825–1,125 |
| Baby blanket | 1,500–1,625 | 1,250–1,500 | 1,125–1,250 | 1,000–1,125 | 875–1,000 | 750–875 | 625–750 |
| Throw / afghan | 3,750–4,125 | 3,500–3,750 | 3,000–3,500 | 2,250–3,125 | 2,000–2,250 | 1,625–2,000 | 1,375–1,625 |
How to Measure for the Swatch Method
- Make the swatch in your project stitch. A cabled swatch and a stockinette swatch from the same yarn weigh very different amounts per square inch.
- Weigh in grams. A kitchen scale that reads whole grams works; a 0.1 g jewelry scale is better for small swatches.
- Read the label for both numbers. You need the skein’s grams and its yards, the ratio between them is what converts weight to length.
- For shawls and triangles, halve the width × length area; a triangle is half its bounding rectangle.
Assumptions and Defaults
- Skeins round up, plus the calculator tells you when the count is within 5% of the next skein.
- Published ranges assume adult sizes and plain-to-lightly-textured stitches. Heavy cables add up to 20%; lace subtracts.
- The custom blanket figure scales the afghan range by area, with a 50 × 60 in throw as the baseline.
- The crochet setting adds 25%, the commonly used allowance for crochet against knitting in the same yarn.
- Meters = yards × 0.9144, shown rounded to ten.
Yarn Questions, Answered
How much yarn do I need for a blanket?
In worsted weight, a blanket needs about 1,000 to 1,125 yd for a baby blanket, 2,250 to 3,125 yd for a throw, and 4,000 yd or more for a queen-bed blanket. Choose your blanket size and yarn weight above for a figure scaled to your numbers, and swatch first if the yarn is expensive, because tension can move these totals by several skeins.
How many skeins of yarn is that?
To turn yards into skeins, divide the yards you need by the yards on one label and round up, so a worsted throw at 3,000 yd in 220 yd skeins takes 14 skeins. Buy one more than the division says, because dye lots change between store visits, and a one-skein shortfall shows as a stripe.
Does crochet use more yarn than knitting?
Yes, crochet uses about a quarter more yarn than knitting for the same size in the same yarn, because crochet stitches wrap the hook more times than a knit stitch wraps the needle, and double crochet uses more than single crochet. Tick I’m crocheting above, and the estimate adjusts to match.
How do I calculate yarn from a pattern I’m resizing?
When resizing a pattern, calculate yarn by area rather than width, since a blanket twice as wide and twice as long takes four times the yarn. Multiply the pattern’s yardage by your area ÷ the pattern’s area, then add a skein for safety.
Can I weigh my yarn to see how much I have?
Yes, you can weigh your yarn to see how much you have: grams on the scale × (yards per skein ÷ grams per skein) gives the yards in hand. A 63 g remnant of a 100 g / 220 yd skein holds 138 yd, and the same arithmetic tells you whether a partial skein is enough to finish.
What are wraps per inch, and do they matter here?
Wraps per inch (WPI) identify a yarn’s weight class when the label is gone: wrap the strand around a ruler and count the wraps in one inch, and worsted runs about 9 to 12 WPI. Once WPI gives you the weight class, read that column of the chart above for your yardage.
Why is my total so different from a friend’s for the same pattern?
Your total can differ from a friend’s for the same pattern because of tension, since two people following one pattern can use amounts a full 20% apart. Looser fabric uses less yarn per square inch but needs more rows, and the two effects never quite cancel, which is why yarn shops recommend the swatch method for sweaters.
Chart source: Lion Brand, “How Much Yarn Do You Need?”