All Health Tools

Health Calculator Methodology

Learn how Vinora calculates BMI, protein, calorie and healthy-weight estimates — including formulas, assumptions, sources and limitations.

Last reviewed: August 2026

Our Approach

Vinora's health calculators combine authoritative reference values and scientifically validated formulas. We explicitly distinguish three types of content:

  • Official reference values — from Australian Government or international authoritative bodies.
  • Scientific formulas — from peer-reviewed literature.
  • Vinora calculation assumptions — modelling parameters used by Vinora, not representing any official recommendation.

All results are estimates for informational purposes only and do not constitute medical advice. See the disclaimer at the bottom of each tool.

Source Hierarchy

Tier 1

Australian Government / NHMRC

Highest priority. Eat For Health, Australian Dietary Guidelines, Dept of Health.

Tier 2

International Authorities

WHO, CDC, NIH, FAO, peer-reviewed scientific literature.

Tier 3

Formulas / Secondary

Validated formulas (Mifflin-St Jeor) used as methodology support only.

BMI Calculator Methodology

Methodology version: 1.1·Last reviewed: August 2026

Formula

BMI = weight (kg) ÷ height² (m²)
Example: 70 kg ÷ (1.70 m)² = 24.2

Rounded to 1 decimal place. Height input: cm (automatically converted to m). Weight input: kg.

Adult Categories (WHO / Australian Standard)

Applies to adults aged 18 and over. Source: Australian Government Department of Health and Aged Care.

CategoryBMI
Underweight< 18.5
Healthy weight18.5–24.9
Overweight25.0–29.9
Obese (Class I)30.0–34.9
Obese (Class II)35.0–39.9
Obese (Class III)≥ 40.0

China Standard (Asian Populations)

Asian populations carry higher body fat at equivalent BMI values. The China standard uses lower thresholds for overweight and obesity.

CategoryBMI
Underweight< 18.5
Healthy weight18.5–23.9
Overweight24.0–27.9
Obese≥ 28.0

BMI Limitations

BMI is a screening measure, not a diagnostic tool.

BMI does not directly measure:

  • Body fat percentage
  • Muscle mass
  • Body composition
  • Cardiovascular fitness
  • Metabolic health

Athletes with high muscle mass may have elevated BMI without poor health. Older adults may have normal BMI but high body fat. This tool is for adults aged 18 and over only.

Sources

Australian Government Department of Health and Aged Care

Body mass index (BMI) and waist measurement

Last reviewed: 2023

Australian Government

World Health Organization (WHO)

Body mass index — BMI

Last reviewed: 2022

International Authority

Protein Calculator Methodology

Methodology version: 1.1·Last reviewed: August 2026

Important distinction

This tool shows two distinct values: ① Australian/New Zealand NRV Recommended Dietary Intake (RDI) from official reference values; ② Vinora personalised estimate based on Vinora's calculation method. They mean different things.

Australian/New Zealand NRV Protein RDI

Source: Eat For Health (NHMRC). The following are adult daily protein Recommended Dietary Intakes (RDI).

PopulationRDI (g/day)RDI (g/kg)
Men 19–7064 g0.84 g/kg
Men 71–70+81 g1.07 g/kg
Women 19–7046 g0.75 g/kg
Women 71–70+57 g0.94 g/kg

Vinora Personalised Estimate Method

The following are Vinora's calculation assumptions. They do not represent Australian Government or any official recommendation.

Vinora estimate = weight (kg) × activity multiplier × goal adjustment

Activity multipliers:
sedentary 0.8 g/kg light 1 g/kg moderate 1.2 g/kg intense 1.4 g/kg
Goal adjustments:
maintain +0 g/kg muscle +0.4 g/kg lose +0.2 g/kg

Sources

Eat For Health (National Health and Medical Research Council)

Nutrient Reference Values — Protein

Last reviewed: 2017

Australian Government

National Health and Medical Research Council (NHMRC)

Australian Dietary Guidelines

Last reviewed: 2013

Australian Government

Calorie Calculator Methodology

Methodology version: 1.1·Last reviewed: August 2026

Step 1 — Estimate Basal Metabolic Rate (BMR)

Uses the Mifflin-St Jeor equation (1990), one of the most widely cited methods for BMR estimation.

Male: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
Female: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161

Step 2 — Estimate Total Daily Energy Expenditure (TDEE)

TDEE = BMR × Physical Activity Level (PAL)

The following activity multipliers are Vinora calculation assumptions. They are not published standards of any official authority.

Activity levelMultiplierDescription
sedentary1.2Little or no exercise
light1.375Light exercise 1–3 days/week
moderate1.55Moderate exercise 3–5 days/week
active1.725Hard exercise 6–7 days/week
veryActive1.9Very hard exercise or physical job

Step 3 — Calorie Target Estimates

Fat loss: TDEE − 500 kcal/day (approx. 0.5 kg/week loss)
Maintenance: TDEE
Muscle gain: TDEE + 300 kcal/day

The −500 kcal deficit and +300 kcal surplus are Vinora modelling assumptions, not Australian Government-prescribed targets.

Unit Conversion

1 kcal = 4.184 kJ

Australian official energy reference values typically use kJ. This tool displays both kcal and kJ.

Sources

Eat For Health (National Health and Medical Research Council)

Nutrient Reference Values — Energy

Last reviewed: 2017

Australian Government

Healthy Weight Range Calculator Methodology

Methodology version: 1.1·Last reviewed: August 2026

Calculation Method

Derived from the adult healthy BMI range of 18.5–24.9. Source: Australian Government Department of Health and Aged Care.

Lower bound = 18.5 × height(m)²
Upper bound = 24.9 × height(m)²

Example (height 170 cm):
Lower = 18.5 × 1.70² = 53.5 kg
Upper = 24.9 × 1.70² = 71.9 kg

Results rounded to 1 decimal place.

Important Limitations

This calculator provides a population-level BMI-based reference range, not an individual's medically optimal weight. Results may not apply for:

  • People with high muscle mass (e.g. athletes)
  • Pregnancy or breastfeeding
  • People with certain chronic conditions
  • Unusual bone structure or body composition
  • Children and adolescents under 18

Sources

Australian Government Department of Health and Aged Care

Body mass index (BMI) and waist measurement

Last reviewed: 2023

Australian Government

Complete Sources List

Australian Government Department of Health and Aged Care

Body mass index (BMI) and waist measurement

Last reviewed: 2023

Australian Government

Eat For Health (National Health and Medical Research Council)

Nutrient Reference Values — Protein

Last reviewed: 2017

Australian Government

Eat For Health (National Health and Medical Research Council)

Nutrient Reference Values — Energy

Last reviewed: 2017

Australian Government

National Health and Medical Research Council (NHMRC)

Australian Dietary Guidelines

Last reviewed: 2013

Australian Government

World Health Organization (WHO)

Body mass index — BMI

Last reviewed: 2022

International Authority

Disclaimer

Vinora's health calculators provide general estimates for informational and educational purposes only. They are not medical advice, diagnosis, treatment, or a substitute for consultation with a qualified healthcare professional. Results are estimates based on the information you provide and the methodology described on this page. Individual health, nutritional, and energy needs can vary significantly. If you are pregnant or breastfeeding, under 18, living with a medical condition, taking medication, managing an eating disorder, or have specific dietary or nutritional needs, consult a qualified healthcare professional before making significant changes to your diet, exercise, or energy intake.

Use the Health Calculators

Health Calculator Methodology | Formulas, Sources & Limitations | Vinora Health