Buying yarn without regret
There are two ways to get this wrong, and both are painful. Buy too little and you face the dye lot lottery, hunting for a matching ball months later. Buy far too much and you've spent money on yarn that will sit in a bag for years.
The figures above lean deliberately towards having a little spare, because running short is much the worse outcome. One extra ball is cheap insurance on a project that will take you weeks.
Always match yardage, never ball count. Two yarns of the same weight can have wildly different yardage per ball — one might give 120 yards per 100 g and another 240. Buying "ten balls" because the pattern says ten balls is the single most common substitution mistake, and it can leave you half a jumper short.
Weighing your stash
Kitchen scales are the crafter's secret weapon. If you know a yarn gives 220 yards per 100 g, then 45 g of it holds about 99 yards. This works for partial balls, wound cakes and mystery leftovers alike, and it's far more reliable than guessing by eye. If you don't know the yardage per 100 g, our chart in the yarn identifier gives typical figures for each weight.
Why yarn weight changes the yardage you need
A chunky jumper and a fingering-weight jumper cover the same body, but chunky yarn is thicker, so fewer yards fill the same space — though each yard weighs more. The calculator adjusts for this automatically when you pick your yarn weight, which is why a chunky throw needs fewer yards than the same throw in DK.
Buy extra for these
- Cables and texture can eat 20 to 30% more yarn than plain stocking stitch.
- Colourwork means carrying floats, which adds up over a whole garment.
- Long or generous sizes — patterns often quote yardage for the smallest size.
- Fringe, tassels and pompoms use more than anyone expects.
Questions we're often asked
How much yarn do I need for a blanket?
A baby blanket takes roughly 800 yards of DK, a generous throw around 2,000 yards, and a double bed blanket 3,000 or more. Chunky yarn needs fewer yards for the same size, fingering considerably more — the calculator adjusts for the weight you choose.
How do I work out yardage from grams?
Divide your yarn's weight by 100, then multiply by the yards-per-100 g figure on the ball band. So 45 g of a yarn that gives 220 yards per 100 g holds about 99 yards.
Can I substitute a different yarn in a pattern?
Yes, as long as the weight matches and you swatch to check your gauge. Work out the total yardage the pattern needs — balls multiplied by yardage per ball — then buy enough of your yarn to reach that total, rounding up.
What is a dye lot and why does it matter?
A dye lot is a single batch dyed together. The same shade from two different lots can differ just enough to show as a faint stripe across a finished piece. Buy all your yarn at once from the same lot, and if you must add more later, work the new yarn in alternate rows to blend the change.
How much extra yarn should I buy?
One spare ball for a garment or blanket is sensible, and more if the pattern uses cables, colourwork or a large size. Leftovers are useful for swatches, repairs and stripes; running out mid-sleeve is not.