F9 is used to manually recalculate the sheet in Microsoft Excel.
A little anachronistic though, no?
I was a junior analyst 25 years ago with not one but two PCs.
Compile excel report on PC 1 and hit F9. Start working on different report on PC 2 while PC1 slowly counts down.
Can’t remember the last time I hit F9 – Oliver Thornton @ Financial Director
Shows how big the improvements in the processing power of the computers used now and systems used then. Now, I don’t have to press F9 to manually recalculate and wait for the results at any time. It is all instantaneous. There may be still use cases for this option when doing big modelling tasks that have great quantum of variables and functions and formulas that are complex; but for most users waiting for Excel to finish running a calculation is over.