Guides to the maths behind your loan
Long-form, plain-English explanations of how loans actually work. Every figure in them is computed with the same engine that powers the calculators, so you can check any claim on the tool it came from.
Amortization explained: where every payment actually goesA plain-English guide to amortization — why early payments are almost all interest, when the crossover happens, and how to read your own schedule with confidence.9 min read
How to pay off your mortgage earlySix ways to clear a mortgage early, what each actually saves in dollars and years, and the cases where overpaying is the wrong move.11 min read
APR vs interest rate: what actually separates themWhat separates APR from the interest rate, which fees are included, and why APR quietly flatters a loan you will not keep for its full term.8 min read
When refinancing actually saves moneyBreak-even maths, the term reset that hides a loss behind a lower payment, cash-out versus rate-and-term, and a checklist for deciding whether to refinance.10 min read
Debt snowball vs avalancheThe maths says avalanche, the evidence on human behaviour says snowball. Here is what each costs, when the gap matters, and a hybrid that captures most of both.9 min read
How your credit score sets your interest rateWhat a credit score is built from, how score bands translate into real rate differences and dollars, and which actions move a score quickly versus slowly.10 min read
Negative equity, and how people stay trapped in itHow buyers end up owing more than the car is worth, what rolling that shortfall into the next loan really costs, and how to get out of an upside-down car loan.9 min read
Compound interest works both waysHow compounding works, why frequency matters far less than people think, the rule of 72, and why the same force that grows savings traps card debt.9 min read
Student loan repayment without guessingRepayment plans compared on total cost, when refinancing federal loans is a mistake, and how capitalisation quietly inflates your balance.10 min read
The first-time buyer's mortgage guideWhat lenders really check, how much deposit you need, every closing cost itemised, and why your payment jumps in year two.12 min read
Or go straight to a calculator
- Amortization scheduleThe whole table, payment by payment, with extra payments and a CSV export.
- Extra payment calculatorWhat $200 a month is worth in interest saved and years removed.
- Refinance break-evenWhen the closing costs are recovered, and whether a new term quietly costs more.
- Compare three offersDifferent rates, terms and fees judged on total cost, not monthly payment.
- Biweekly vs monthlyWhether fortnightly payments are worth it, and how to get the same result free.
- Mortgage calculatorPrincipal, interest, tax, insurance, PMI and HOA in one honest number.
- Auto loan calculatorTrade-in, negative equity, sales tax and dealer fees, all financed.