Excel formula that tells how much month left to reach target savings.

I m trying to write a formula but either the logic isnt right or i am not able to create it.

I m going to give you a scenario. Please code this.

I want to save $10,000 in 12 months.
How much do I have to save per month to reach my target amount from current month and date.
Suppose $10,000 / 12 = 833.33 per month

But if I deposit $933.33 how much earlier I can reach my target amount.?

The problem here is to figure out how much earlier (month) i can reach the target amount
For example if its 12 then if I deposit more than I planned to save the month should change from 12 to 11 or 10 depending upon the amount.


Target month = 12 or any number.
Target Amount = $10,000
Contribution required = $833.33 to reach in 12 months from current date/month (formula)

If deposit $933.33
Target month which I set $10,000 to reach in 12 months.

The target month should change and say now you can reach this amount in 10 months.

I tried alot and confused to a point i cant figure this out anymore.
This seems really simple but not able to code this.



Thanks
- Fadu

I put together a small "table for you...

	A	B
1	Target Month	12
2	Target Amount	$10,000.00
3	Contribution Reqired	$ 833.33
4
5	Actual Amount	933.33
6	Actual Month	10.7

B3=B2/B1
B6=B2/B5

You can change B1, B2 and B5 to play with values