Guides

Longer explainers that sit behind the calculators. How the maths works, which rules apply where, and what the numbers mean once you have them.

8 min readHow Loan Calculators WorkUnderstand the math behind loan calculations and how to use them to make better borrowing decisions.
10 min readUnderstanding Compound Interest: The Eighth Wonder of the WorldLearn how compound interest works, why Einstein allegedly called it the most powerful force in the universe, and how to harness it.
7 min readBMI Explained: What It Is, How It's Calculated, and Its LimitationsA comprehensive guide to Body Mass Index. What it measures, how to interpret it, and when other metrics matter more.
9 min readRetirement Planning Basics: Start Building Your Future TodayEssential concepts and strategies for planning a comfortable retirement, including the 4% rule, contribution strategies, and investment choices.
6 min readThe Complete Guide to Unit ConversionMaster the art of converting between metric and imperial units for everyday use and professional applications.
8 min readStatistics Fundamentals: Understanding DataLearn the core concepts of statistics including mean, standard deviation, distributions, and when to use each measure.
7 min readBusiness Math Essentials: Numbers Every Business Owner Should KnowMaster the key financial calculations that drive business success. From margins to break-even to ROI.
7 min readFitness Calculations: The Science Behind Your WorkoutUnderstand the math behind one-rep max, calorie burn, heart rate zones, and other key fitness metrics.
8 min readEssential Engineering Formulas and CalculationsKey formulas and calculation methods used in civil, mechanical, and electrical engineering.
6 min readKitchen Math: Essential Calculations for Every CookMaster recipe scaling, measurement conversions, and cooking math for perfect results every time.
9 min readMortgage Amortisation: Where Your Repayment Actually GoesWhy early repayments are almost all interest, what an extra $100 a month is really worth, and how offset accounts and redraw change the maths.
9 min readInvestment Returns: Compounding, Diversification and the Fees That Eat ThemHow returns actually accumulate, why average returns mislead, and the small number of decisions that determine most long-term outcomes.
7 min readHow Income Tax Is Calculated: Brackets, Deductions and WithholdingThe mechanics behind any progressive income tax system. Marginal versus average rates, what a deduction is worth, and why refunds happen.
9 min readAustralian Income Tax: How It Actually WorksBrackets, marginal rates, the Medicare levy, offsets and why your refund is not a bonus. The 2026-27 system explained end to end.
8 min readHECS-HELP in 2026: Thresholds, Indexation and Whether to Pay It OffHow the marginal repayment system works, why indexation timing matters more than you think, and when a voluntary repayment is worth making.
9 min readSuperannuation: The 12% Rate, the Caps, and the Levers That MatterHow super is taxed, what the contribution caps mean in practice, and the handful of decisions that move a retirement balance materially.
8 min readStamp Duty Across Australia: What Each State ChargesHow transfer duty is calculated in each state and territory, what first home buyer concessions are actually worth, and the thresholds that create hard cliffs.
10 min readInvestment Property in Australia: Gearing, Yield and the Tax at the EndHow negative gearing, depreciation, rental yield and the capital gains discount fit together, and the numbers that decide whether a property works.
8 min readCalories, TDEE and Why the Numbers Only Get You StartedHow energy expenditure is estimated, how accurate those estimates really are, and how to adjust a target using what actually happens.
7 min readBeyond BMI: Measuring Body Composition HonestlyWhat BMI can and cannot tell you, how body fat estimates actually work, and which measurements are worth tracking over time.
8 min readProbability and Odds: Reading Chance Without Fooling YourselfIndependent versus dependent events, why the gambler's fallacy is so persuasive, and how base rates make accurate tests misleading.
8 min readReading Data Without Being Fooled: Averages, Spread and SamplingWhen the mean misleads, what standard deviation actually tells you, and how to judge a survey or a headline statistic.
8 min readOhm's Law and Electrical Load: The Practical BasicsVoltage, current, resistance and power explained for real circuits, plus why load calculations and circuit sizing are licensed work.
9 min readRoof Pitch, Slope Factor and Ordering Roofing MaterialsWhy a roof is always bigger than the building under it, how pitch is quoted three different ways on the same job, and how to order materials without a second delivery.
8 min readWhen Refinancing a Mortgage Actually Saves MoneyBreak-even maths, why a lower rate over a longer term can cost more, and the one move that captures the whole benefit of a rate cut.
9 min readNPV, IRR and Payback: Evaluating a Capital InvestmentHow to decide whether equipment, software or an acquisition is worth buying, and why payback period quietly favours the wrong projects.
8 min readVO2 Max: What It Measures and How to Improve ItThe single best field measure of aerobic fitness, how to test it without a laboratory, and the training that actually moves it.