--- title: "Ideal Weight Calculator New Zealand: Six Formulas | AumnI tools" description: "Enter height to compare six ideal weight formulas in kilograms, then see the weight range for the Ministry of Health healthy BMI band at that height." url: https://aumnitools.com/nz/tool/ideal-weight-calculator category: "Health" country: "New Zealand" updated: 2026-11-08 --- # Ideal Weight Calculator Ideal weight formulas rarely agree, and New Zealand guidance for adults relies on BMI bands rather than any one target. This page runs Robinson, Miller, Devine, Hamwi, Broca and Lorentz in kilograms, averages them, and prints the healthy weight range from the Ministry of Health bands. Your GP can help you decide what applies to you. ## New Zealand rules and figures - The Ministry of Health adult guideline gives Healthy weight as BMI 18.5 to 24.9 and one Obesity band from 30, which is why the ranges here have no obesity classes. - Asian descent may mean a lower healthy BMI, according to Health NZ, and the Ministry suggests lower waist thresholds; no figures appear in either source. - Kilograms and centimetres are what the New Zealand page starts with, so results are printed in kg. - Separate Ministry clinical guidelines cover children and young people, so the adult ranges on this page do not apply to them. Sources: [Ministry of Health: Weight management in adults (2017)](https://www.health.govt.nz/system/files/2017-11/weight-management-in-adults-01-aug-18.pdf) (checked 2026-11-08); [Health NZ: Healthy weight BMI calculator](https://www.healthnz.govt.nz/health-topics/keeping-healthy/eating-well/healthy-weight-bmi-calculator) (checked 2026-11-08); [Ministry of Health: Weight management in children and young people](https://www.health.govt.nz/system/files/2011-10/clinical-guidelines-weight-management-nz-children-young-people-dec16.pdf) (checked 2026-11-08) ## How the ideal weight calculator works The formulas run on your height and gender, and the results are rounded to one decimal place in kilograms before being shown. Formula: `Miller (men) = 56.2 + 1.41 × (inches − 60) kg. Hamwi (men) = 48 + 2.7 × (inches − 60) kg` - Metric is the starting unit system, with 170 cm entered. A different unit, such as stones and pounds, is remembered once you pick it. - The Ministry bands used here have a single Obesity band from 30, so there is no class split in the ranges, only Underweight, Healthy weight and Overweight. - With a weight entered, the page tells you if it is inside the healthy band or how far above or below it you are. - Tracked entries and goals are stored in kilograms, whatever unit is on screen. ## How to use the ideal weight calculator 1. **Choose how to enter height.** Leave Height Unit on centimetres, or switch to feet and inches. 2. **Add your weight if you want a comparison.** Type kilograms into the optional box to see where you sit against the healthy band. 3. **Pick gender.** The Profile tab's Gender setting selects between men's and women's versions of the formulas. 4. **Look at the six figures and the bands.** The calculator tab lists each formula and then the BMI-based ranges. 5. **Save, copy or export.** Use Save Entry for a dated record, Copy for the clipboard or Export for a file. ## Example: 175 cm woman and 183 cm man At 175 cm a woman's six results run from 62.5 kg (Lorentz) to 66 kg (Devine) with an average of 64.4 kg, and her healthy band is 56.7 to 76.3 kg. At 183 cm a man averages 76 kg, from 73.2 (Miller) up to 80.5 (Hamwi), with a healthy band of 62 to 83.4 kg. ## When to use the ideal weight calculator - **Comparing six estimates.** Look at how far apart Hamwi and Lorentz are for your height before treating any single number as a target. - **Finding a healthy kilogram range.** Use the BMI-based band for your height as a starting point for a GP discussion. - **Following progress.** Save weights over time and compare them with the band on the Tracking tab. ## What the ideal weight calculator does not do - The six formulas see only height and gender, so muscle, frame and age are ignored. - Health NZ and the Ministry give no numbers for Asian ethnicities, so one band is applied to all. - Activity Level, Body Type and Calculation Method are stored but have no effect on the results. - This page offers estimates only. A GP can advise on a weight that fits your health. ## When something else is a better fit - **When you want the Ministry of Health BMI label for a given weight**, use the [BMI Calculator](https://aumnitools.com/tool/bmi-calculator.md). - **When you want an estimate from neck and waist measurements**, use the [Body Fat Calculator](https://aumnitools.com/tool/body-fat-calculator.md). - **When you need a goal for a specific health condition**, use your GP or a dietitian, who can use your health history. ## Questions about the ideal weight calculator ### What is the ideal weight for my height in New Zealand? There is no single figure. The six formulas give a spread, and the Ministry healthy band is 18.5 to 24.9 BMI. At 175 cm the band is 56.7 to 76.3 kg and the formulas average 64.4 kg for a woman. ### Why does the Underweight range start at 16? The calculator uses a BMI of 16 as the floor of the Underweight range it prints, and goes up to just under 18.5. The Healthy weight range starts at 18.5. ### Is the result different for Asian ethnicities? The Ministry and Health NZ say lower thresholds may apply, without numbers, so this page uses the standard band. Your GP can advise how that affects your target. ### How do I switch to stones? Change Weight Unit to st and the results appear in stones and pounds. The formulas are still worked out in kilograms, and the unit you chose is kept. ## 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/nz/tool/ideal-weight-calculator