How it works
BMI uses weight and height to create a general adult screening number. This page also estimates a healthy weight range for the entered height and can show a waist-to-height ratio when waist is provided.
BMI result
Enter adult height, weight and age to calculate BMI and related screening notes.
This calculator is for general informational use only. BMI is a screening tool, not a diagnosis. It does not measure body composition directly and does not replace medical advice from a qualified healthcare professional.
If you are pregnant, under 20, managing a medical condition, recovering from an eating disorder, or concerned about your weight, speak with a healthcare professional.
When to use this tool
Use it for a quick adult body mass index check, a general healthy weight range, or extra waist context before discussing personal health questions with a qualified professional.
Waist check explanation
Waist circumference can add context because BMI does not show body shape or where weight is carried. This is still a screening note, not a diagnosis.
Women and pregnancy note
The calculator is neutral for adult users, but pregnancy changes interpretation. During pregnancy, use pre-pregnancy BMI and speak with a healthcare professional for pregnancy weight guidance.
Practical guidance
Example use
Enter age 32, height 170 cm and weight 70 kg to calculate BMI and see an approximate weight range for BMI 18.5-24.9 at that height.
Limitations
BMI does not account for muscle mass, bone structure, pregnancy, age-specific child percentiles, medical history or individual health goals. Treat the result as a broad screening number only.
Privacy note
The calculation runs in your browser. ToolForge Online does not require an account for this tool and the values are used on the page to generate the result.
Last updated
Last updated: June 2026.
FAQ
How is BMI calculated?
In metric units, BMI equals weight in kilograms divided by height in meters squared. In imperial units, BMI equals 703 times weight in pounds divided by height in inches squared.
What BMI range is considered healthy for adults?
For many adults, BMI from 18.5 to below 25 is commonly described as a healthy weight range. This is a general screening range, not a personal medical target.
Why add waist circumference?
Waist circumference can add context because BMI does not show how weight is distributed. The waist note is still only a screening signal and should not be read as a diagnosis.
Is BMI different for women?
The basic adult BMI formula is the same. Interpretation can still vary by pregnancy status, health history, body composition and personal context, so the result should be handled carefully.
Can I use this calculator during pregnancy?
You can see the mathematical BMI value, but ordinary adult BMI categories should not be used as current pregnancy guidance. Use pre-pregnancy BMI and talk with a healthcare professional.
Is this medical advice?
No. This is a general informational calculator. It does not diagnose, treat, prescribe food choices, or replace a qualified healthcare professional.
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