One dropdown, the whole lending desk
Pick the question you are asking — "what is the payment?", "which loan wins?", "when does this card die?", "what are these flows worth?" — and the form adapts to exactly the inputs that question needs. Every member uses the textbook formula and prints it back with your numbers substituted, so you can check the arithmetic by hand.
The conventions this page uses
All payments are end-of-period (ordinary annuity — the first payment comes one period after the money is received). Monthly rates are r = APR ÷ 12, with no day-count fine print. Taxes, insurance, and fees are ignored unless a field explicitly asks for them. For NPV, IRR, and payback, the first flow in the list is time 0 — the investment itself — and later flows land at the end of each period after it.
Worked example
- A $200,000 loan at 6% APR for 360 months.
- Monthly rate r = 6% ÷ 12 = 0.005; n = 360.
- PMT = 200,000 × 0.005 ÷ (1 − 1.005^−360) = $1,199.10 per month.
- Total repaid ≈ $431,677 — of which $231,677 is interest.
How to use it
- Choose the question from the "Which question?" dropdown.
- Fill the fields it shows — rates go in as percents (6, not 0.06), cash-flow lists as comma-separated numbers.
- Read the headline number, the row breakdown, and the substituted formula beneath the board.
- Try a preset or edit the numbers to compare scenarios; the share link keeps your member and values.