For field C use this calculation:
A * (1 + B)
For field D use this calculation:
C - A
Edit: fixed small mistake
Brilliant, it works a treat. The only problem that the percentage field B wont let me put in 1.98%, i have to put in 0.0198 to get it right, is there a quick way to sort this out?
A massive thank you for your help
That's how percentage fields work. Their values are from 0 (=0%) to 1 (=100%).
If you want a field that works with values from 0 to 100 then you can use a regular Number field, maybe with a custom Format script to add the percentage symbol.
In that case you'll need to change the first formula to:
A * (1 + B/100)
1 person found this helpful
That's absolutely brilliant and works really well.
many many thanks, sorry to be so thick!!