BMI Calculator for Mounjaro
Find your BMI, see which category it falls into, and understand how it relates to eligibility criteria for treatments like Mounjaro.
BMI (Body Mass Index) is one of the screening tools used to assess whether someone may benefit from weight-loss medication. In the UK, treatments like Mounjaro are generally considered for adults with a BMI of 30 or above, or 27+ with weight-related health conditions.
This calculator shows your current BMI, what category it falls into, and the weight benchmarks for your height.
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What this calculator does
This calculator computes your BMI from your height and weight, classifies it into standard categories (underweight, healthy, overweight, obese), and shows benchmark weights for each category at your height. If you enter a target weight, it shows what your BMI would be at that weight.
Who it is for
Anyone wanting to check their BMI, especially those considering weight-loss medication and wanting to understand how BMI relates to treatment eligibility criteria.
How to use it
Enter your current weight and height. Optionally enter a target weight to see what your BMI would be after weight loss. Click 'See My Result'.
How the calculation works
BMI = weight (kg) ÷ height (m)². We then classify the result using standard WHO/NHS categories: Underweight (<18.5), Healthy (18.5–24.9), Overweight (25–29.9), Obese class I (30–34.9), Obese class II (35–39.9), Obese class III (40+).
Worked example
Weight 95 kg, height 170 cm: BMI = 95 ÷ (1.70)² = 32.9 — Obese class I. Healthy weight range for 170 cm = 53.5–72.2 kg. Weight to lose to reach healthy range = 22.8 kg.
Assumptions and limitations
- BMI is a screening tool and does not account for muscle mass, body composition, age, sex, or ethnicity
- NICE recommends lower BMI thresholds for some ethnic groups (e.g. South Asian populations)
- BMI alone does not determine medication eligibility — clinical assessment is required
- Children and adolescents use age-adjusted BMI percentiles, not this calculator
Frequently asked questions
What BMI do you need for Mounjaro?
In the UK, Mounjaro (tirzepatide) is generally considered for adults with a BMI of 30 or above, or 27+ with at least one weight-related health condition (such as type 2 diabetes, high blood pressure, or sleep apnoea). Eligibility is determined by a clinician.
Is BMI accurate?
BMI is a useful screening tool but has limitations. It does not distinguish between muscle and fat, and may underestimate health risks in some ethnic groups. It should be used alongside other assessments, not as a sole measure.
What is a healthy BMI?
A BMI between 18.5 and 24.9 is classified as healthy weight by the NHS and WHO. However, health depends on many factors beyond BMI, including waist circumference, blood pressure, and metabolic markers.
Related calculators
- Mounjaro Calorie Calculator — Calculate your maintenance calories and a safe deficit range to support steady weight loss alongside Mounjaro treatment.
- Mounjaro Calorie Deficit Calculator — Enter your maintenance calories and a target intake (or desired weekly loss) to see the size of your deficit and projected weight change ove
- Mounjaro Protein Calculator — Find out how much protein you should aim for each day and per meal to support muscle preservation during weight loss on GLP-1 medication.
- Mounjaro vs Wegovy Calculator — Enter your weight and the monthly costs of each medication to compare projected weight loss, total spend, and cost per kilogram lost over yo
- Mounjaro Weight Loss Calculator — This planning tool projects how much weight you could lose over a chosen number of weeks, using conservative, moderate, or ambitious assumpt
Related guides
- What BMI Means for Weight-Loss Injections — How BMI is used to assess eligibility for weight-loss medications like Mounjaro and Wegovy, and its limitations.
- Mounjaro vs Wegovy for Weight Loss — A balanced comparison of Mounjaro (tirzepatide) and Wegovy (semaglutide) — mechanism, effectiveness, cost, and side effects.
- How Much Weight Can You Lose on Mounjaro? — A realistic look at expected weight loss on Mounjaro (tirzepatide), based on clinical trial data and practical planning advice.
- How Much Protein Should You Eat on Mounjaro? — Why protein matters during GLP-1 weight loss and how to hit your daily target with practical meal guidance.
- How Many Calories Should You Eat on Mounjaro? — Understanding your calorie needs during Mounjaro treatment — maintenance, deficit, and safe intake ranges explained.
Sources and references
NHS BMI calculator (https://www.nhs.uk/live-well/healthy-weight/bmi-calculator/), WHO BMI classification, NICE TA1026 tirzepatide eligibility criteria
Last updated
Last reviewed: 2025-04-12.