Leitner

Learn finance by running the numbers yourself

Finance is arithmetic with consequences, and the arithmetic is not hard — what is hard is developing a feel for how violently small changes compound over time. You get that by moving the inputs and watching the curve, not by being told the formula. The block below is one of those: it names the year the interest starts out-earning you.

What compounding does to a monthly habit, and the year the interest starts out-earning you.

Chart · compound growthYEAR 22 IS THE TURN
balanceyearsyear 22
Paid in$60k
Interest$79k
Final balance$139k

From year 22 the interest is doing more of the work than you are: everything above the green line is money the account made on its own. Over 25 years you pay in $60k and it earns $79k.

Start a finance planThe first lesson of every plan is free

What people come here to do

You describe the goal in your own words and it asks questions back until the plan is one you would actually follow. These are the shapes that goal usually takes.

  • Get through a corporate finance module
  • Understand my own pension and mortgage properly
  • Prepare for a finance interview
  • Read a set of accounts without bluffing

What a finance plan covers

Not a fixed syllabus — the plan is built around your goal and cuts what does not serve it. These are the topics it draws from, and whatever you get wrong comes back until it stops coming back.

Compound interest and the time value of money
Discounting, NPV and IRR
Reading a balance sheet and income statement
Risk, return and diversification
Valuation and cost of capital
Debt, equity and capital structure

Other subjects

The mechanics are the same whatever the subject — a slider is a slider whether it is moving a coefficient or a rate of return. What changes is what it is a slider for.

Or see how it works and what it costs.