If you're creating an item with a different yarn to what is suggested (substituting a yarn) in your pattern, you won't necessarily need the same amount of balls your pattern specifies. It all depends on the yards or meters per ball.
Yarn is sold by weight not length, so it's important to work out how many yards or meters you need. Each brand of yarn and each fibre may have a different length per ball, so you need to calculate the total needed in the recommended yarn.
My pattern calls for 6 x 50g of 'lovely wool' which has 100m per ball. So I need at least 600m.
I would prefer to use 'fluffy wool' which has 150m per 50g ball or 'fantastic wool' which has 90m. So I will need:
Number of total meters needed / Length of the yarn you would like to use = number of balls
So using our Fluffy and Fantastic wool examples,
600 / 150 = 4 balls of 'Fluffy wool' = 600m
600 / 90 = 6.6 balls of 'Fantastic wool' = 600m
We always round up to the nearest round number, so you would need 7 balls of Fantastic wool
You can see on the ball band how many meters or yards there are on average in each ball, and you can also find this out in the product information on our site. If you are not sure please contact us - we are happy to help!