Guides
Short explainers that show the working behind our calculators, so you can judge the results for yourself.
How Mortgage Payments Work
A plain-English guide to how a mortgage payment is built, why early payments are mostly interest, what escrow adds, and how extra payments change the cost.
How to Read Your BMI Result
What BMI measures, how it is calculated, what the standard categories mean, and when BMI is misleading. A practical guide, not medical advice.
Compound Interest Explained
How compound interest works, with the formula, worked examples, compounding frequency, regular contributions, the Rule of 72 and the effect of inflation.
About these guides
Each guide takes one topic that our calculators handle and explains the working step by step: the formula, a worked example with real numbers, the common mistakes and the limits of the result. They are written for readers who want to check a number rather than simply trust it.
How Mortgage Payments Work breaks a monthly payment into principal and interest, explains why early payments are mostly interest, and shows what escrow and extra payments change. How to Read Your BMI Result covers the formula, the adult categories and the situations where BMI is misleading. Compound Interest Explained walks through the formula, compounding frequency, regular contributions, the Rule of 72 and the effect of inflation.
Every guide links to the calculators it describes, so you can try your own figures as you read. The guides are general information, not financial or medical advice, so confirm important decisions with a qualified professional.