Explore guide
How much replacement yarn do two labels imply?
Convert an original ball count into required length, then round replacement balls once.
Related lessons and tools
Compare length before counting balls
If a project calls for three original balls of 200 m, its stated quantity is 600 m. With a chosen 10% allowance, plan for 660 m. Replacement balls containing 150 m and weighing 50 g require five balls, providing 750 m and 250 g.
Three original balls do not automatically become three replacement balls. Package weight alone cannot establish equivalent length.
Read both labels
Record the original ball count and length per ball. From the replacement label, record length and package weight. Keep each figure attached to the correct yarn. The Craft Yarn Council label guide explains standardized yarn-label information; the example here uses invented package figures for teaching.
Work through the quantities
- Original quantity: 3 × 200 m = 600 m.
- Apply the selected allowance once: 600 m × 1.10 = 660 m.
- Divide by replacement length: 660 ÷ 150 = 4.4 balls.
- Round the purchase quantity upward: five whole balls.
- Record the supplied totals: 5 × 150 m = 750 m and 5 × 50 g = 250 g.
The remaining 90 m is the difference between the rounded package total and the allowance-adjusted requirement. It is not another allowance to add. If the pattern quantity already includes a reserve you intend to retain, choose 0% extra instead of automatically adding 10%.
Check whether the yarn is suitable
Length equivalence is only a quantity calculation. Compare fiber behavior, construction, working gauge, drape, elasticity, and care. Finish a representative sample and measure it before buying a project quantity. A matching yarn-weight category or needle recommendation does not establish the same fabric.
Unknown original length cannot be recovered from ball count alone. Find the original package specification or estimate from a suitable sample; do not replace missing facts with these example values. Treat separate colors as separate requirements, and do not pool unlike materials.
The planner below starts in original-label mode and uses the same substitution method as the standalone tool. Its suitability questions remain yours to answer. Report label or arithmetic problems through corrections.
Sources for sampling and terminology
Yarn substitution planner
Turn required yarn length into whole substitute balls, total length, and weight.
Before you use this tool
Use the original total length, or original ball count × length per ball, then enter the replacement label length. Equal ball weights do not imply equal lengths.
Read quantity and suitability separately: enough yarn may still give the wrong fabric. Confirm washed gauge, drape and care before committing.
Method and limits
Formula and assumptions
Required length plus allowance is divided by substitute length per ball and rounded up. Risk also reflects fiber, yarn structure, blocked gauge, weight category, care, and drape; unknown or different properties require a swatch before purchasing.
Worked example
Example: 850 m plus 10%, using 175 m and 50 g balls, requires 6 balls: 1,050 m and 300 g purchased.
Limits and rounding
Results are planning estimates from the values entered. Displayed decimals are rounded for craft use; whole materials and repeats round up where the method says so. Confirm gauge, material behavior, construction, and finished measurements before committing supplies.