BMI calculator and blood pressure check
Enter your height and weight to see your body mass index (BMI), what category it falls in and the weight range considered healthy for your height. Switch to the blood pressure tab to see where a reading sits.
Your weight is in the range associated with the lowest health risks for most adults.
- Healthy weight range for your height
- 118 – 159 lb
- →
- You are within the healthy range.
For adults, for information only. This tool does not give medical advice or a diagnosis. Ask a health professional about your results.
How to use it
- Choose metric or imperial units and enter your height and weight.
- Read your BMI, your category and the healthy weight range for your height. Add your waist size if you want the waist-to-height ratio.
- Open the blood pressure tab, enter the systolic (top) and diastolic (bottom) numbers and read the category.
Guide
What BMI tells you and what it does not
Body mass index compares your weight to your height. It is widely used because it is simple and tracks well with health risks across large groups of people. For one person it has limits: it cannot tell muscle from fat, where fat is stored, or how fit you are. Treat it as a starting point for a conversation, not a verdict.
BMI categories for adults
Under 18.5 is underweight, 18.5 to 24.9 is the normal range, 25 to 29.9 is overweight, 30 to 34.9 is obesity class 1, 35 to 39.9 is class 2 and 40 or more is class 3. These cut-offs come from the World Health Organization. Some research suggests different thresholds may fit some populations better, so your doctor may interpret yours differently.
Why waist size matters too
Fat stored around the waist is linked with more heart and metabolic risk than fat elsewhere. A simple check is the waist-to-height ratio: keeping your waist under half your height is a commonly used target. It is a useful companion to BMI, especially when BMI looks normal but the waist is large.
Blood pressure and your heart
High blood pressure usually causes no symptoms, yet over the years it strains the heart and arteries and raises the risk of heart attack and stroke. The top number (systolic) is the pressure when the heart beats and the bottom number (diastolic) is the pressure between beats. Regular checks, less salt, more activity, a healthy weight and not smoking all help keep it in range.
When to see a doctor
See a doctor if your blood pressure readings are repeatedly 130/80 or higher, if your BMI is in the obesity range or below 18.5, or if you have chest pain, breathlessness or sudden weakness. Heart attack risk depends on age, cholesterol, smoking, diabetes and family history, so it needs a proper assessment that no online calculator can replace.
Frequently asked questions
How is BMI calculated?
BMI is your weight in kilograms divided by your height in metres squared. A person who weighs 70 kg and is 1.70 m tall has a BMI of 70 ÷ (1.70 × 1.70), about 24.2. In pounds and inches, multiply weight by 703 and divide by height squared.
What is a normal BMI?
For adults, the World Health Organization defines 18.5 to 24.9 as the normal range. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or more is obesity, which is further split into three classes.
Is BMI accurate?
BMI is a quick screening number, not a diagnosis. It does not tell fat from muscle, so a very muscular person can have a high BMI without excess fat. It also does not apply to children, pregnancy or older adults in the same way. Waist size and a check-up give a fuller picture.
What is a normal blood pressure?
A reading below 120/80 mmHg is generally considered normal. Readings of 130/80 or more are classed as high blood pressure stages, and a reading above 180/120 needs urgent medical attention if you also have symptoms. One reading is not a diagnosis: take several, rested and seated.
Can this tool tell me my risk of a heart attack?
No. Heart attack risk depends on many factors, including age, cholesterol, smoking, diabetes and family history, and it has to be assessed by a doctor with validated scores. BMI and blood pressure are two of the factors, so this tool helps you spot when it is worth getting checked.