The calculation chain
Safe. On by default.
Removes the saved order Excel last calculated formulas in.
Why it takes space
Excel records the order it last calculated every formula in, and saves that list inside the file as calcChain.xml. The list holds one entry per formula cell, so a workbook with hundreds of thousands of formulas carries a long one.
The chain records only an order. It holds no formula and no value, and Excel shows it nowhere.
What ShrinkExcel does
ShrinkExcel deletes the calculation chain. The file format treats it as optional, and Excel builds a new one from the formulas themselves, whatever the old one held.
It keeps the chain when the workbook uses iterative calculation, the setting that lets formulas refer to themselves in a loop. Under that setting the order formulas run in can change a result.
What you will notice
Nothing on the sheets changes. Every formula keeps its text and the value it last showed.
In a check in Excel for Mac on 2026-09-24, four formula-heavy workbooks gave the same values without the chain after a full recalculation, and Excel wrote a new chain when it saved them.
Doing it in Excel
Excel has no command that removes the calculation chain.
It runs on every workbook you drop on the front page, unless you switch it off under Advanced settings.