The reference desk
Financial maths, explained without shortcuts.
Plain-language guides to interest, options payoffs, mortgages, retirement modelling and tax estimates. Every guide states what the model includes, what it leaves out and which calculator lets you test the assumptions.
Investing
Compound interest, contribution by contribution
How time, deposits and an assumed rate interact.Options
How to read an options payoff graph
Profit, loss, breakeven and expiration risk in one frame.Mortgages
What a mortgage payment estimate leaves out
Principal, interest, taxes, insurance and affordability assumptions.Retirement