Guides
Guides
Twenty plain guides, each starting with the answer, then the formula, worked examples and sources. Each one links to the free calculator that does the sum.
Updated 21 October 2026. Sources named on the page.
- Answer first, then the formula and a worked example
- Every figure names its source
- Kilojoules and calories side by side
- For healthy adults aged 19 and over; not medical advice
Every claim names its sourceNothing you type is savedFree, no sign upFor adults aged 19 and overPrivate by default
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Food and calories
How many calories should I eat a day?Calories needed depend on age, sex, size and activityWhat is a calorie deficit?A calorie deficit means eating fewer calories than you useHow to calculate TDEETDEE is your resting energy times an activity factorActivity level explainedThe answer, the formula and worked examples.kJ vs caloriesKilojoules and calories both measure food energyHow to read nutrition labels in AustraliaThe answer, the formula and worked examples.
Protein and macros
How much protein do I need a day?The answer, the formula and worked examples.Protein per kg by ageThe answer, the formula and worked examples.How to calculate macrosTurn a daily calorie target into grams of protein, carbohydrate and fatMacro split examplesThe answer, the formula and worked examples.
Sleep and water
How much sleep do I need?Most adults need 7 to 9 hours of sleep a night, and older adults often 7 to 8How many sleep cycles do you need?Most adults aim for 5 or 6 sleep cycles of about 90 minutes, or 7.5 to 9 hoursHow much water should I drink a day?The answer, the formula and worked examples.Hydration mythsThe answer, the formula and worked examples.
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