Calculating compound interest per period over several years for an investment

It's been a long time since I've had to do this and I've simply forgotten how. Can someone please help me with the formulas in the attached excel file?

I've found 2 reliable online calculators and I've hard-coded the values for compound interest in the attached excel file. I just need to figure out how to calculate these myself for a project that I'm working on.

Full details are in the attachment.

Thanks in advance for the help!

Leith,
Thanks for the help.

I apologize as I should have explained that I've tried that formula and it works in total (ie. for the length of time in years and for the total compounded interest), but I'm not able to apply this formula in a manner that delivers the compounding numbers as found on the 2 websites that I had listed in my excel attachment (both examples were from reputable online companies and both have the same graphical results that I'm trying to obtain so I'm trusting that their numbers are accurate).

I think the difference that I'm looking for is a problem because of annual investments (ie. cash flow/changing total investment balance every year), but I'm not sure.

Here's one of the examples that I'm tying to tie my compound interest numbers to, for each year starting year 1 and ending year 12. http://personal.fidelity.com/toolbox...h/growth.shtml - if you change the values on this web page to 12 years, Initial Balance $100,000, annual investment $1,000, deselect the Increase Annual Investment with Inflation, Rate can be left as 8%, 0% for tax and 0% for inflation (easiest way to get the graph and numbers to update is input one of the values needed and press "Enter" on keyboard) - once you have $58072 for compound interest, $102240 Simple Earnings and $112000 Amount Invested that's correct and that's the results I'm looking to duplicate in Excel. I have the Investments and Simple Interest, but I need to get this Compound Interest calculated and on a per year basis (notice that graph, when moused over, shows the values at each year)

Would you be able to tell me precisely how the formula should look in the cells I've highlighted?

Thanks again!!!

Originally Posted by kmham

Leith,
Thanks for the help.

I apologize as I should have explained that I've tried that formula and it works in total (ie. for the length of time in years and for the total compounded interest), but I'm not able to apply this formula in a manner that delivers the compounding numbers as found on the 2 websites that I had listed in my excel attachment (both examples were from reputable online companies and both have the same graphical results that I'm trying to obtain so I'm trusting that their numbers are accurate).

I think the difference that I'm looking for is a problem because of annual investments (ie. cash flow/changing total investment balance every year), but I'm not sure.

Here's one of the examples that I'm tying to tie my compound interest numbers to, for each year starting year 1 and ending year 12. http://personal.fidelity.com/toolbox...h/growth.shtml - if you change the values on this web page to 12 years, Initial Balance $100,000, annual investment $1,000, deselect the Increase Annual Investment with Inflation, Rate can be left as 8%, 0% for tax and 0% for inflation (easiest way to get the graph and numbers to update is input one of the values needed and press "Enter" on keyboard) - once you have $58072 for compound interest, $102240 Simple Earnings and $112000 Amount Invested that's correct and that's the results I'm looking to duplicate in Excel. I have the Investments and Simple Interest, but I need to get this Compound Interest calculated and on a per year basis (notice that graph, when moused over, shows the values at each year)

Would you be able to tell me precisely how the formula should look in the cells I've highlighted?

Thanks again!!!

Hi,

amended : removed original post

The attached, a modification of what I use to calculate interest, has Green totals that agree with the site mentioned, perhaps this will assist you to balance your figures.

hth
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