Excel automatically calculates all the formulas within a worksheet.
When there are complex formulas or a large data set, Excel’s performance slows down. This is because it calculates after every change or update.
You may spend more time waiting on Excel to finish than you do on updating or entering information.
To solve this problem, you can set the calculation option from Automatic to Manual. Then you can use the application’s features to manually recalculate formulas.