Knitting and Crochet Yarn Calculator

1. Enter the finished width and length of your project in inches.
2. Choose the yarn weight, from lace to super bulky.
3. Enter the yards per ball from your yarn label.
4. Read how many balls and total yards you need.

A yarn calculator estimates how much yarn a knitting or crochet project needs before you buy. It works from the finished size and the yarn weight, because thinner yarns take far more yards to cover the same area than thick ones. Getting this right avoids the two classic problems: running out mid-project, or buying far too much.

The estimate suits flat, mostly solid pieces such as blankets, scarves, wraps and dishcloths. Complex shaping, colourwork and openwork change the amount, so treat the figure as a well-judged starting point.

1. Multiply width by length for the finished area.
2. Multiply by a yards-per-square-inch factor for the yarn weight.
3. Add 15 percent for swatches, seams and mistakes.
4. Divide by the yards per ball and round up.

Finer yarns use a higher factor: lace covers an area with about 2.5 yards per square inch, while super bulky needs only around 0.55.

For a 40 by 60 inch worsted blanket, the area is 2,400 square inches. At 1.1 yards per square inch that is 2,640 yards, and adding 15 percent gives about 3,036 yards. With 200-yard balls you would buy 16 balls. Switch to bulky yarn and the same blanket needs far fewer yards but thicker, heavier balls.

Yarn Weight

The single biggest factor. Fine yarns take two to four times the yards of bulky yarn for the same finished size.

Stitch Pattern

Dense cables and colourwork use more yarn than plain stockinette, while lacy openwork uses less because it is full of holes.

Gauge and Tension

Knitting tighter than the pattern gauge packs in more stitches and uses more yarn, so always check your swatch.

Shaping and Seams

Garments with sleeves, ribbing and seams need extra yarn beyond the flat area, which the 15 percent margin helps cover.

Knitting vs Crochet

Crochet is thirstier than knitting. The same stitches worked in crochet typically swallow around a third more yarn, because the fabric is denser and each stitch wraps more times. If you are crocheting rather than knitting, lean toward the higher end of the estimate or add a little more to the safety margin, so a granny-square blanket or an amigurumi toy does not leave you a ball short near the finish line.

Yarn weight sets both the look and the yardage.

Buy all the yarn for a project in the same dye lot so the colour matches across every ball.

Before Buying Yarn

Work out the balls to buy so you get enough in one dye lot.

Substituting Yarn

See how switching weight changes the amount when a pattern yarn is unavailable.

Stash Projects

Check whether the yarn you already own is enough for the piece you want to make, so a treasured skein is not started and then abandoned halfway.

1. Ignoring Yarn Weight

Estimating by area alone, without weight, can be off by several balls.

2. Skipping the Margin

Always add spare for swatches, seams and errors, or you risk running short.

3. Mixing Dye Lots

Buying too little means a later ball from a different lot may not match.

4. Forgetting Gauge

Knitting looser or tighter than the pattern changes the yarn used.

This is a planning estimate for flat, solid pieces. Real use varies with pattern, gauge and shaping.

A worsted-weight throw of about 40 by 60 inches needs roughly 2,600 to 3,000 yards, or around 16 balls of 200 yards, including a safety margin.

Multiply the finished width by the length for the area, multiply by a yards-per-square-inch factor for your yarn weight, then add about 15 percent and divide by yards per ball.

Yes, a lot. Fine yarns can take two to four times the yardage of bulky yarn to cover the same area.

Add about 10 to 15 percent for swatches, seams and mistakes, and always buy in a single dye lot.

A dye lot is a batch dyed together. Balls from different lots can vary slightly in colour, so buy enough of one lot up front.

Crochet generally uses more yarn than knitting for the same area, often around a third more, so lean toward the higher end.

It varies widely, commonly 100 to 400 yards. Always check the label, since the calculator uses the figure you enter.

No. The calculator runs entirely in your browser and nothing you enter is stored or sent anywhere.

• About yarn and yarn weight (Wikipedia).
• Knitting basics (Wikipedia).
• Crochet basics (Wikipedia).