Normally each 100 gram ball or skein of Guernsey yarn will be around 232 metres (242 yards) long, but this varies from breed to breed, so to be on the safe side you should work on plus or minus 10%.  This densely twisted worsted spun yarn is not elastic so will go less far than a woollen spun yarn, and it’s worth getting a couple of balls extra for a pullover project, to be on the safe side and match the batch numbers.
 
Fibre: 100% Romney Wool
Weight: 100g 5ply
Meterage: 232 metres approx
Gauge: 30 sts and 40 rows to a 10cm/4" square
Needles:  on 2.25mm
Worsted spun
 
You can also work a Guernsey yarn as a 4-ply or DK to make a less dense fabric, but with excellent stitch definition. For example, on 4mm/US 6, UK 8 needles, you will get around 22 sts and 30 rows to a 10cm/4″ square. But remember that this yarn is less elastic, so you may need more yarn than stated in a pattern, unless it is specifically for a Guernsey design. The WPI is usually 20 in worsted spun yarns.