Free Guides on Health & Finance

Plain-English explanations of the maths behind everyday decisions — each one paired with a free calculator so you can run the numbers yourself.

🩺 Health Guides

How to Calculate BMI: Formula, Chart & What It Really Means

The BMI formula step-by-step, the WHO category chart, and an honest look at where the number falls short — especially for athletes and older adults.

How Many Calories Should I Eat Per Day? (TDEE Explained)

Why the "2,000 calories a day" recommendation is almost meaningless for most people, and how to calculate your personal TDEE using the Mifflin-St Jeor equation.

Heart Rate Training Zones Explained: Zone 2, Fat Burn & VO2 Max

What each of the 5 heart rate zones actually does, why Zone 2 is the most underused by recreational exercisers, and how to find your personal zone boundaries.

How Much Water Should You Drink Per Day? A Practical Guide

Why "8 glasses a day" is too simple, how body weight and activity change your requirement, and what urine colour actually tells you about hydration.

💰 Finance Guides

How Compound Interest Works: The Simple Guide With Real Examples

Simple vs compound interest, the formula, the Rule of 72, what happens when you add monthly contributions, and why compound interest on debt is the same force working against you.

How to Pay Off Your Mortgage Faster: 7 Strategies That Actually Work

From biweekly payments to mortgage recasting, with real interest savings calculations for each approach — and an honest look at when early payoff isn't the best use of money.

🏖️ Finance

Retirement Planning: How Much Do You Actually Need to Retire?

The 4% rule explained clearly, savings benchmarks by age, how Social Security factors in, and what to do if you're behind where you want to be.

🍽️ General

How Much to Tip: The Complete Tipping Guide for Every Situation

Current US tipping standards across restaurants, hotels, rideshares, salons, and delivery — including when it's genuinely okay not to tip.