Keep the original band
The most useful clues are the labelled length and yarn weight, such as 120 metres in a 50-gram ball. If a leftover is still attached to a wrapper or bobbin, weigh that holder separately and subtract it. A kitchen scale gives an estimate, not a guarantee of how far the yarn will go in a new stitch pattern.
Use a simple proportion
First divide the original length by the original yarn weight. With 120 metres in 50 grams, each gram represents about 2.4 metres. If the leftover yarn weighs 18 grams, multiply 18 by 2.4: about 43.2 metres remain. Round sensibly and leave a margin instead of planning a project that requires the final few centimetres.
Check the limitations
- Use the band for that exact yarn, not another ball that merely looks similar.
- Subtract the weight of any packaging, holder or needle on the scale.
- Remember that scale precision, moisture and label tolerances affect the estimate.
- Make and weigh a sample if you are trying to estimate how many repeats a particular stitch will use.
Choose a low-risk use
A small decorative sample, repair or colour accent can be a better choice for an uncertain leftover than an essential final row of a gift. Keep enough tail for secure finishing. If you will change colour when the yarn runs out, decide where that change should happen before you reach it.
Words in this lesson
Tare weight
The weight of the container or holder, subtracted to find the yarn weight.
Length per gram
Labelled length divided by labelled yarn weight.
Notes & further reading
Original explanations and practice exercises by Crochet By Micky. UK stitch names are used; check the stitch key in any other pattern you follow.
Reviewed 25 October 2026. Cover artwork is an original illustration, not a third-party pattern or event photograph.