# Yarn substitution planner

> Turn required yarn length into whole substitute balls, total length, and weight.

- [Open tool](https://threadcabin.com/tools/yarn-substitution-planner)
- The page shows its formula, example, assumptions, rounding, and limitations beside the calculator.

## 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.