Methodology.
Every calculator on My Finance Tools is built on standard financial formulas and best practices. Here's a plain-language summary of the main methods, so you can check the work.
Compound interest
The standard compounding formula, where A is the future value, P the principal, r the annual rate, n the compounding frequency, and t the number of years.
Investment return
Simulates growth period-by-period with options for fees, inflation, taxes, withdrawals and recurring contributions, using iterative calculations so each variable compounds correctly over time.
Mortgage
Calculates monthly payments and a full amortization schedule using the standard loan amortization formula, separating principal from interest for every period.
Wealth multiplier
Shows the combined effect of compounding and inflation over long horizons, applying the same principles as above to illustrate real versus nominal growth.
Have a question about how something is calculated? Contact me. I'm happy to walk through any of it.