--- title: "Ideal Weight Calculator Australia: Six Formulas in kg | AumnI tools" description: "Enter height in centimetres to compare six ideal weight formulas in kilograms, with the Department of Health healthy BMI band for the same height shown beside them." url: https://aumnitools.com/au/tool/ideal-weight-calculator category: "Health" country: "Australia" updated: 2026-11-08 --- # Ideal Weight Calculator Six classic formulas estimate an ideal weight from height and gender, and they rarely agree. This page runs all six in kilograms for Australian users, averages them, and shows the weight range inside the Department of Health healthy BMI band, 18.5 to 24.9. Treat each figure as a rough guide and ask a GP what suits you. ## Australia rules and figures - Kilograms and centimetres are the opening units on the Australian page, so every result is printed in kg with no conversion step. - The Department of Health uses WHO cut-offs for adults, so the healthy band is 18.5 to 24.9 and Overweight starts at 25. - The Department says the healthy range is generally lower for those of Asian background and higher for those of Polynesian background, but supplies no numbers, so this page applies the standard band. - The Department's adult categories stop at 18, and its note on BMI for teenagers says the measure is less reliable for them. Sources: [Australian Government Department of Health: BMI and waist measurement](https://www.health.gov.au/topics/overweight-and-obesity/bmi-and-waist) (checked 2026-11-08) ## How the ideal weight calculator works Height converts to inches for Robinson, Miller, Devine and Hamwi and stays in centimetres for Broca and Lorentz, then each result is rounded to 0.1 kg. Formula: `Robinson (women) = 49 + 1.7 × (inches − 60) kg. Broca (women) = (H − 100) × 0.85, H in centimetres` - Height and weight open in metric, with 170 cm entered and kilograms shown. A unit you choose, such as feet and inches, stays selected. - The average is of all six results, worked out before rounding, so it can differ by 0.1 kg from averaging the printed values. - The BMI-Based Weight Ranges use 18.5 up to 24.9 for Healthy weight, with 16 as the floor of the Underweight range and 25 to 29.9 for Overweight. - Heights under 100 cm or over 250 cm return no result. ## How to use the ideal weight calculator 1. **Enter a height.** Type centimetres in the box, or change the unit to feet and inches and fill both boxes. 2. **Give your weight.** The kilograms box is optional. With a weight entered, the page tells you whether it is inside the healthy BMI band. 3. **Set gender.** Open the Profile tab and choose Gender. The women's and men's formulas use different starting weights. 4. **Compare the formulas.** Individual Formula Results shows all six, and BMI-Based Weight Ranges sits below them. 5. **Save an entry.** Save Entry adds a dated row to the Tracking tab, which stays in this browser. ## Example: 160 cm woman and 170 cm man in kilograms A woman of 160 cm sees 54.1, 57.2, 52.4, 52.1, 51 and 55 kg from the six formulas in the order Robinson to Lorentz, which average 53.6 kg. Her healthy BMI band runs from 47.4 to 63.7 kg. A man of 170 cm averages 65.3 kg across the six, with a healthy band of 53.5 to 72 kg. ## When to use the ideal weight calculator - **Spotting the spread.** Compare Hamwi and Miller for your height to see how far the six estimates sit apart. - **Getting a kilogram range.** Read the healthy band in kilograms for any height between 100 and 250 cm. - **Logging weight against a target.** Save entries with notes and compare them with a target weight on the Goals tab. ## What the ideal weight calculator does not do - Only height and gender go into the formulas, which leaves frame, muscle and age out of every figure. - The Department gives no numbers for Asian or Polynesian backgrounds, so the same band applies to everyone here. - Calculation Method (Standard, Athletic, Elderly) is stored but does not change any result. - A single ideal weight is a simplification, and a GP can talk through what is realistic and healthy for you. ## When something else is a better fit - **When you want a BMI number with its Department of Health label**, use the [BMI Calculator](https://aumnitools.com/tool/bmi-calculator.md). - **When you want body composition from tape measurements**, use the [Body Fat Calculator](https://aumnitools.com/tool/body-fat-calculator.md). - **When you need a weight goal that fits a medical condition**, use a GP or accredited practising dietitian, who use your history and tests. ## Questions about the ideal weight calculator ### Which formula is the most accurate? None is, for every person. Each uses height and gender only, so the page shows all six and their average. For a woman of 160 cm they span 51 to 57.2 kg. ### How is the healthy BMI weight range calculated? It is height in metres squared times 18.5 at the bottom and times 24.9 at the top. At 160 cm, 1.6 squared is 2.56, giving 47.4 to 63.7 kg. ### Does my age change the results? No. Age is stored in the profile and only triggers a tip for people over 65. Height and gender alone move the six formulas. ### Why is there no result for a 90 cm height? The calculator accepts 100 to 250 cm only. Outside that range it shows a prompt, and the same limits apply if the height is given in feet and inches. ## Related tools - [BMI Calculator](https://aumnitools.com/tool/bmi-calculator.md): Works out BMI and its category from height and weight, with the healthy weight range - [Body Fat Calculator](https://aumnitools.com/tool/body-fat-calculator.md): Estimates body fat from neck, waist and height tape measurements with the US Navy formula - [Calorie Calculator](https://aumnitools.com/tool/calorie-calculator.md): Estimates BMR and daily calorie needs, with gram targets for protein, carbs and fat ## About this page Runs in your browser: what you enter is processed on this device and is not uploaded. Your profile, goals and weight history are kept in local storage on this device only, including entries you have deleted until you empty Recently deleted. General information only, not medical advice. Talk to a doctor or other health professional about decisions that affect your health. Last checked against the tool's code on 2026-11-08. Interactive version: https://aumnitools.com/au/tool/ideal-weight-calculator