Is there some way using Excel that I can (easily) calculate a final balance amount after starting with a principal and adding extra money monthly?

So here’s formula for compound interest:

=P*(1+r)ⁿ

where P is the principal/initial amount, R is the interest rate and N is the number of years.

Let’s say I start with zero in an account that has a rate of 4.3%. Each week for 1 year I put $125 into the account. How can I work out how much will be in the account at the end of the 1 year period?

JTQ said:

Is there some way using Excel that I can (easily) calculate a final balance amount after starting with a principal and adding extra money monthly?

So here’s formula for compound interest:

=P*(1+r)ⁿ

where P is the principal/initial amount, R is the interest rate and N is the number of years.

Let’s say I start with zero in an account that has a rate of 4.3%. Each week for 1 year I put $125 into the account. How can I work out how much will be in the account at the end of the 1 year period?

How often is the interest calculated and paid?

It would depend on how often the interest is calculated and credited.

Sorry JTQ, we don’t do people’s homework here.

:-P

JTQ, with that equation you need to know how often the interest is calculated.

So if is calculated monthly then r = 0.043/12 and n = 12.

Interest calculated and paid monthly.

OCDC said:

Sorry JTQ, we don’t do people’s homework here.

:-P

lol .. I’m no longer a student :) just thinking about refinancing some things..

JTQ said:

Is there some way using Excel that I can (easily) calculate a final balance amount after starting with a principal and adding extra money monthly?

So here’s formula for compound interest:

=P*(1+r)ⁿ

where P is the principal/initial amount, R is the interest rate and N is the number of years.

Let’s say I start with zero in an account that has a rate of 4.3%. Each week for 1 year I put $125 into the account. How can I work out how much will be in the account at the end of the 1 year period?

Also you started saying adding money monthly, and then said adding it weekly. Which one?

JTQ said:

OCDC said:

Sorry JTQ, we don’t do people’s homework here.

:-P

lol .. I’m no longer a student :) just thinking about refinancing some things..

Hence the :-P

Stealth said:

JTQ said:

Is there some way using Excel that I can (easily) calculate a final balance amount after starting with a principal and adding extra money monthly?

Also you started saying adding money monthly, and then said adding it weekly. Which one?

ooops… yeh it’d have $125 paid weekly, not monthly. Interest paid monthly is what I meant to put in the top line.

OCDC said:

JTQ said:

OCDC said:

Sorry JTQ, we don’t do people’s homework here.

:-P

lol .. I’m no longer a student :) just thinking about refinancing some things..

Hence the :-P

:) long day at work, and 10 mins left.

Just visit any bank website, they all have savings calculators.

http://www.patrickschneider.com/blog/2008/03/compound-interest-with-an-initial-balance-and-monthly-contributions/

I haven’t read it but I suspect its the droid you are looking for

How come none of you braneiacs gave JTQ an excel formula for this?

Useless, the lot of you.

sibeen said:

How come none of you braneiacs gave JTQ an excel formula for this?

Useless, the lot of you.

I’d do it row by row (and use an average monthly payment, rather than try to deal with payments and interest arriving at different times
Row 1:
A1: Starting amount
B1: A1*interest/12
C1: Monthly contribution
D1: = Sum(A1:C1)

Row 2:
A2: = D1
Other cells as Row 1.

Just copy row 2 down for as many rows as you want.

Rev, doesn’t excel do iteration?

sibeen said:

Rev, doesn’t excel do iteration?

Can do, but it’s easier just to iterate by copying.

The Rev Dodgson said:

sibeen said:

Rev, doesn’t excel do iteration?

Can do, but it’s easier just to iterate by copying.

Ta. I didn’t have a clue.

In mathcad it’s just a few lines, and if you wanted to know the result after 2000 months I’d hate to do it by copying :)