Yarn Skein Calculator
Balls to buy for a project's yardage.
Calculate how many balls or skeins a project needs from the total yardage required and the yardage per ball.
One spare from the same dye lot is cheap insurance — lots differ visibly and shops rarely have yours weeks later.
Balls to buy
6
4.55 balls of yarn needed
Gauge changes this more than people expect. Knitting the same pattern at a tighter gauge puts more stitches into the same area and uses more yarn, and a size up can add 20% on top of that.
How the Yarn Skein Calculator works
Balls are the unit you buy in and yardage is the unit patterns are written in, so the conversion is a division and a round up. The round up is not optional and the spare ball usually is not either: dye lots differ visibly, and the shop will not have yours in three weeks.
Also known as: how many balls of yarn calculator · yarn quantity calculator
How the number is derived
Total yardage divided by yardage per ball, rounded up. The rounding up is not a safety margin — it is that balls are indivisible — so the real decision is how many spares to add on top.
For a garment the answer is at least one. Dye lots differ enough to show as a band across a sweater, and a ball bought weeks later from a different lot rarely matches well enough to hide. Buying the spare at the same time is the only reliable protection.
For a scarf or a blanket where a subtle stripe would not matter, the spare is optional and the leftover is the cost.
A worked example
A sweater needing 1,000 yards in 220 yard balls: 4.55 balls, so five, plus one spare is six. Five balls give 1,100 yards, a 100 yard margin — which sounds comfortable until a longer body or a bind-off that takes more than expected eats it.
The same sweater one size up commonly needs 15 to 20% more yarn, which is 1,150 to 1,200 yards and six balls before any spare. Size is a bigger driver of yardage than most people allow for.
Where the answer misleads
Gauge changes the yardage substantially and in the opposite direction to intuition. Knitting tighter puts more stitches into the same area, so a tighter gauge uses more yarn for the same garment, not less.
Stitch pattern matters as much. Cables and heavy texture can use 20 to 30% more yarn than stocking stitch over the same area, because the fabric is pulled in and there is more length in every stitch. A pattern's yardage is for its own stitch pattern only.
Finally, published yardages are for the sample size and the sample's ease. A garment knitted with more positive ease than the sample needs proportionally more yarn, and the pattern rarely says so.
Frequently asked questions
How many skeins of yarn do I need?
Divide the total yardage the pattern calls for by the yardage on your ball band, then round up. A 1,000 yard project in 220 yard balls needs 4.55, so five balls.
Should I buy a spare ball?
For any garment, yes. Dye lots vary enough to show as a visible band across a sweater, and a ball bought later from a different lot rarely matches. A spare from the same lot is cheap insurance against a re-knitted sleeve.
What if the pattern gives balls rather than yardage?
Convert to yardage first by multiplying the ball count by the yardage of the yarn the pattern used. Buying the same number of balls of a different yarn is how people run out — a substitution calculator handles that case properly.
Does gauge affect how much yarn I need?
Yes, more than people expect. Knitting the same pattern at a tighter gauge puts more stitches into the same area and uses more yarn, and a larger size compounds it. A size up can add 20% to the yardage.