# Blocking change projection

> Project finished dimensions from the measured change in your blocked swatch.

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

## Formula and assumptions

Width and height use their own measured after-to-before ratios. This is a projection from your swatch, not a safe stretching target.

## Worked example

Example: a swatch changing from 10 × 10 cm to 11 × 9 cm projects a 50 × 60 cm piece to about 55 × 54 cm.

## 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.