Your description leaves a lot to be desired.

What do you want to calculate? The monthly payment? The initial amount? What
does "got left against a new" mean?

You will want a financial function. You can check out the functions PV, FV,
NPER, or PMT. One of these will do what you want.

Or, post back with a clearer explanation of what you want to do. An example
would be extremely useful.

Regards,
Fred

"colin devine" <colin wrote in message
...
I want to be able to set an interest rate, fix a monthly budget, set a
baloon/final payment, so that i can see clearly how much depost i've got
left
against a new