This is a spreadsheet application that helps you follow the year by year progress of a retirement, or any other, investment account. It is a model for a single account.
Estimating the outcome of a retirement investment, or any investment for that matter, requires guessing what will happen in the future. It would be too difficult, and perhaps meaningless, to enter estimates for each year on items like interest rates, income, Broker’s fee. So, it makes sense to use estimated averages over the life of the model, like 20, 40 years or more. Here, these are called “lifetime average”. This involves assumptions, called what if’s, such as, “What if the interest earned is 5%, 7%, or 10% a year on the average over the life time of the investment?” “What if I invest 5%, 7%, or 10% of my income a year on the average over the lifetime of the investment?” “What if the my income grows 3%, 5%, or 7% a year on the average over the lifetime of the investment?”
In this spreadsheet application you enter “lifetime average” estimates of items, as described below. It displays the output as Year-by-year results.
There are two model for the applying the interest. One, the Simple model, compounds the interest annually. The second, FV model, uses a Future Value algorithm that gives the result of compounding the interest monthly.
The Model: Inputs and Outputs
The Inputs, you enter
1. Your “first year” income.
2. The following lifetime averages:
a) % annual increase in your income,
b) % of present income saved each year,
(this could be the sum of the contributions from your income
and from your employer(s))
c) % annual interest earned on the net principle of your account,
d) broker’s fee as a % of the net principle of your account,
e) % annual increase in inflation .
Year-by-year results on a are displayed. See Layout and Glossary for details.