Guides
Short, practical explainers on how everyday calculations actually work — the thinking behind the tools.
How to Calculate the Time Between Two Dates
Working out how much time separates two dates sounds simple, but month lengths and leap years make it surprisingly easy to get wrong. Here's how it really works.
Percentages Made Simple: Of, Out Of, and Change
Most percentage confusion comes from mixing up three different questions. Once you can tell them apart, the maths is easy.
Understanding BMI, Calories and Healthy Weight
BMI, calorie needs and 'ideal weight' are useful starting points for thinking about health — as long as you know what they can and can't tell you.
Everyday Money Maths: Tips, Discounts and Loan Payments
A handful of simple calculations cover most day-to-day money decisions. Here's the maths behind tips, discounts and loan repayments.
Metric and Imperial: A Quick Conversion Guide
Switching between metric and imperial units comes down to a few key conversion factors. Learn the important ones and the rest follow.