How do I limit a value in a formula, or create a formula with multiple calculations?

I need to create a formula the allows me to calculate:
Bonus earned after £12500 up to £20000 at a rate of 10%, then after £20000 the bonus rate becomes 12.5%

Is there a way to do this? Or

I need to stop the 1st part of the calculation at the £20000 mark so I can the create a 2nd calculation and add the 2 totals together.

I hope this makes sense, and that someone can help, my brain is about to EXPLODE!!!

Thanks

You can use the MIN and MAX functions..

=(MIN(20000,A1)*10%)+(MAX(0,A1-20000)*12.5%)

What does A1 represent, sorry, im relatively new to excel.
the first calculation i am using that i want to limit to 750 is the bonus from 12500 to 20000 at 10%
=SUM(I24-12500)/100*10
the second calculation is bonus over 20000 at 12.5%
=SUM(I24-20000)/100*12.5
I24 is currently set at 20000 but is frequently changed

Perhaps

=MIN(12500,MAX(0,SUM(I24-12500)))/100*10

And

=MIN(20000,MAX(12500,SUM(I24-20000)))/100*12.5%

Great thanks I will give these a try, thank you again!