How the swatch method works
A swatch is the most reliable way to estimate yarn because it captures everything that changes the answer: the yarn's thickness, the stitch pattern, your hook or needle size and how tightly you work. The calculator turns your swatch into a rate and scales it up.
- Yarn per square inch = yards in the swatch ÷ (swatch width × swatch height).
- Project yarn = yarn per square inch × project width × project length.
- Yarn to buy = project yarn plus the safety margin, rounded up to a whole yard.
- Skeins = yarn to buy ÷ yards per skein, rounded up.
If you weighed the swatch, the calculator first converts grams to yards with the ball band: swatch grams × (skein yards ÷ skein grams).
Yarn for common blanket sizes
The chart uses one example swatch, 6 × 6 inches that used 24 yards, with a 10 percent margin and 200-yard skeins. It shows how yarn scales with size, not what your yarn will take: a denser stitch or a heavier yarn uses more yards per square inch, so run your own swatch through the calculator.
| Blanket | Size | Area (sq in) | Yarn with 10% margin | 200-yard skeins |
|---|---|---|---|---|
| Lovey | 14 × 14 in | 196 | 144 yd (132 m) | 1 |
| Stroller | 30 × 35 in | 1,050 | 770 yd (705 m) | 4 |
| Baby | 36 × 36 in | 1,296 | 951 yd (870 m) | 5 |
| Throw | 50 × 60 in | 3,000 | 2,200 yd (2,012 m) | 11 |
| Twin | 66 × 90 in | 5,940 | 4,356 yd (3,984 m) | 22 |
| Full | 80 × 90 in | 7,200 | 5,280 yd (4,829 m) | 27 |
| Queen | 90 × 100 in | 9,000 | 6,600 yd (6,036 m) | 33 |
| King | 108 × 100 in | 10,800 | 7,920 yd (7,243 m) | 40 |
Yarn grows with area, so doubling both the width and the length takes four times the yarn.
Example: yarn for a throw blanket
You want a 50 × 60 inch throw and have knitted a 6 × 6 inch swatch in the blanket's stitch pattern, washed and dried the same way you will treat the blanket.
- The swatch weighs 12 g. The ball band says 200 yards per 100 g, which is 2 yards per gram, so the swatch used 12 × 2 = 24 yards.
- The swatch is 6 × 6 = 36 square inches, so it uses 24 ÷ 36 = 0.667 yards per square inch, two-thirds of a yard.
- The throw is 50 × 60 = 3,000 square inches: 3,000 × ⅔ = 2,000 yards.
- With a 10 percent margin that is 2,200 yards (2,012 meters), or 11 skeins of 200 yards.
Tips for an accurate estimate
- Make a real swatch. Use the same yarn, the same needles or hook and the same stitch as the project. A swatch of at least 6 × 6 inches averages out uneven edges better than a small one.
- Use a scale that reads 0.1 g if you have one. On a 12 g swatch, a 1 g rounding error is more than 8 percent of the result.
- Measure after blocking. Wash and dry the swatch the way you will wash the finished piece, then measure it. Many yarns grow or shrink when wet.
- Garments are several rectangles. Add up the area of the back, front and both sleeves, using the average width of a tapered sleeve. Add ribbing, collars and button bands as their own rectangles.
- Borders, fringe and seams need yarn too. Add a border's area to the project, or raise the margin. Fringe and tassels can take a surprising amount, so cut one and weigh it.
- Colorwork is its own swatch. Stranded knitting carries floats behind the work, so it uses more yarn per square inch than plain stitches. Swatch the colorwork and split the total by color.
Frequently asked questions
How much yarn do I need for a blanket?
It depends on the yarn, the stitch and your tension, so measure a swatch. If a 6 × 6 inch swatch used 24 yards, a 50 × 60 inch throw takes 2,000 yards, or 2,200 yards with a 10 percent margin. That is 11 skeins of 200 yards.
How do I find out how much yarn my swatch used?
Weigh it. Divide the yards on the ball band by its grams to get yards per gram, then multiply by the swatch weight. A 12 g swatch of a 200 yd / 100 g yarn used 24 yards. You can also measure the yarn before you start or unravel the swatch and measure it.
Does crochet use more yarn than knitting?
Usually, yes. Crochet stitches are thicker and denser than stockinette, so the same area in the same yarn generally takes more yarn. How much more depends on the stitch, which is why you should swatch in the exact stitch you plan to use.
How many skeins do I need if my yarn has a different yardage than the pattern's?
Compare yards, not skeins. Multiply the pattern's skeins by its yards per skein, then divide by the yards on your skein and round up. A pattern calling for 10 skeins of 200 yards needs 2,000 yards, which is 10 skeins of a 220-yard yarn (9.09 rounded up).
How much extra yarn should I buy?
The calculator adds 10 percent for tails, seams and a swatch that measured slightly off. Buy every skein from the same dye lot, because a later lot can be a visibly different shade. Many shops take back unopened skeins, but check the store's policy first.
Last updated October 17, 2026.