Measure consistently
Use measured height and weight only if seeing the number is safe for you. It is reasonable to skip the calculator and contact support directly.
Low BMI screening and support
Low BMI & Eating-Disorder Support
Calculate an adult BMI and optionally describe recent weight change without claiming that BMI diagnoses—or rules out—an eating disorder.
The calculation runs locally in this browser. Educational outputs do not replace professional assessment, diagnosis, treatment or emergency care.
Method and interpretation guide
Use the low BMI screening result as a transparent estimate
Use measured height and weight only if seeing the number is safe for you. It is reasonable to skip the calculator and contact support directly. The worksheet exposes its assumptions so the result can be checked instead of accepted as a black box.
Read the assumptions
BMI is not an eating-disorder diagnostic test and must not be used as an absolute threshold for access to care or admission decisions.
Escalate important decisions
A calculator cannot examine symptoms, medical history, medication effects or measurement quality. Use qualified professional guidance when the decision has health consequences.
Local calculation
Inputs are processed in this browser. No account or external calculator is required to produce the result.
False precision
Extra decimal places do not remove biological variation, input error or limits in the underlying population equation.
Scope
BMI is not an eating-disorder diagnostic test and must not be used as an absolute threshold for access to care or admission decisions.
Simple by design
Three steps to a clearer number.
Enter your details
Use realistic values in each field. You can change them anytime.
Calculate instantly
The formula runs locally, so there is no account or waiting time.
Use the result
Treat the answer as a practical estimate for your next decision.