A2. If the value increases in A1 by more than 20

If you mean that there is some arbitrary value in A1 and if this arbitrary
value increases by 20 then you will need VBA event code to do this because
otherwise you will get a circular reference error because you will be trying
to refer to the previous value in A1 and the present value in A1.

If you mean when the value in A1 increases TO more than 20 then in B1 try:

=IF(A1<"",A2+INT(A1/20)*A3,"")


--
HTH

Sandy

Replace@mailinator with @tiscali.co.uk


"MCrum" wrote in message
...
How do I use a "IF" comaand. I have a value for instance in A1 and a value
in
A2. If the value increases in A1 by more than 20 I need to add another
value
from A3 to A2 and get a total in B1. If over 40 I need to add A3 again
etc..

Any help would be good.