BMI threshold checker for UK weight loss medicine
Work out your BMI and see how the figure sits against each published UK threshold: private prescription, NICE and the NHS rollout.
Compiled by GLP IndexSources checked Official UK sources only. Not medical advice
Your details
The thresholds used
- Private prescription: a BMI of 30 or more, or 27 or more with a weight related condition. Source: MHRA.
- NICE for Mounjaro: a BMI of at least 35 with at least one weight related condition. Source: NICE.
- NHS GP practices in England: a BMI of 40 or more with at least four of five listed conditions, then 35 to 39.9 with four in the second year. Sources: NHS England, NHS England.
- NHS specialist services for Wegovy: a BMI of 35 or more, or 30 to 34.9 with other criteria. Source: NHS England.
- Thresholds for NICE and the NHS drop by 2.5 for the ethnic backgrounds listed. Source: NHS England.
This tool compares a number with published thresholds. The result is not a medical assessment or a decision. A UK prescriber decides whether a treatment suits you.
Questions
How is BMI worked out?
Weight in kilograms divided by height in metres squared.
Does the checker tell me if I will get a prescription?
No. The checker compares your BMI with published thresholds. A prescriber makes the decision after checking your health.
Why is there an ethnicity option?
NICE and NHS thresholds are 2.5 lower for people from South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean backgrounds.
Is my data stored?
No. The sum runs in your browser. Nothing you enter is sent to GLP Index.
Official sources
Every rule on this page comes from the sources below. GLP Index checked each one on 8 October 2026.
- Medicines and Healthcare products Regulatory Agency. UK first in Europe to authorise orforglipron for weight management and type 2 diabetes. 10 August 2026.
- National Institute for Health and Care Excellence. Tirzepatide for managing overweight and obesity (TA1026). Published December 2024.
- NHS England. Weight management injections. Checked 8 October 2026.
- NHS England. Interim commissioning guidance: NICE TA1026 tirzepatide. Reviewed April 2026.