Why my Google Sheet takes 20 seconds to recalculate

Someone sent me a model last week and I almost closed the tab. Changed one assumption and sat there for like 20 seconds waiting for it to catch up. The file wasnt even big.

I used to dig through formulas one by one when this happened. Now I just run Workbook Health and see what the sheet is actually spending time on.

Its usually one of two things.

Whole-column lookups. VLOOKUP or XLOOKUP pointed at A:A instead of A2:A500. Sheets still walks a million empty cells every time you type. Shrink the range to the rows you actually use and it gets way faster.

Dead tabs. Old "v2 copy" sheets, last quarters stuff, tabs nobody opens. They still recalculate in the background. If you dont need them, delete them or move them to another workbook.

Ive had files where fixing those two was enough. Same model, hit enter, updates normally.

Workbook Health is in XLKeys if you want the scan without hunting manually. Install it here.