Free · Adult & Child · Instant

Height Weight Calculator

Calculate your BMI and healthy weight range instantly — with separate modes for adults and children — plus a body metrics log to track your progress over time.

✓ Free Forever ✓ Adult & Child Modes ✓ Progress Log

Height Weight (BMI) Calculator

Please fill in all fields with valid values.

Bonus Tool

Body Metrics Log

Track your weight and BMI over time. Add an entry after each calculation, and we'll show you the trend versus your previous entry.

DateWeightBMITrend
Calculate your BMI above, then click "Add to Log" to start tracking.
The Method

How BMI Is Calculated

Standard BMI Formula

BMI = Weight (kg) ÷ [Height (m)]²

Adult BMI Categories

Underweight: BMI below 18.5 Normal: BMI 18.5 – 24.9 Overweight: BMI 25.0 – 29.9 Obese: BMI 30.0 and above

Child and teen BMI is interpreted differently — using an age- and gender-specific percentile rather than fixed categories, since healthy BMI changes naturally as children grow.

Worked Example

Step-by-Step Example

An adult, 170 cm tall, weighing 70 kg.

1
Convert height to metres: 170 cm = 1.70 m
2
Square the height: 1.70² = 2.89
3
Divide weight by that: 70 ÷ 2.89 = 24.2
4
Category: BMI 24.2 falls in the Normal range (18.5-24.9)
Reference

Healthy BMI Weight Range by Height

Weight range corresponding to a healthy BMI of 18.5-24.9, by height.

HeightHealthy Weight Range
150 cm (4'11")41.6 - 56.0 kg
160 cm (5'3")47.4 - 63.7 kg
170 cm (5'7")53.5 - 71.9 kg
180 cm (5'11")59.9 - 80.6 kg
190 cm (6'3")66.8 - 89.9 kg
Honest Limitations

What BMI Doesn't Tell You

BMI is a useful screening tool, but it has well-known blind spots.

LimitationWhy It Matters
Doesn't distinguish muscle from fatMuscular individuals often show "overweight" BMI while having low body fat
Doesn't measure fat distributionWaist circumference is a better predictor of some health risks
Not age-specific for adultsBody composition shifts with age at the same BMI
Different for childrenRequires percentile interpretation, not fixed categories
Who Uses This

Common Ways People Use This Calculator

🏋
Fitness Tracking
Monitor BMI alongside your workout progress.
👶
Parents
Check a child's BMI percentile and healthy growth.
📊
Weight Loss Goals
Track changes during your weight loss journey.
🩺
Health Check-Ups
Get a quick health screening before appointments.
🎓
Students
Use BMI for health education and assignments.
👩‍⚕️
Nutrition Planning
Estimate healthy weight targets before diet planning.
👤
Personal Wellness
Understand whether your weight is in a healthy range.
📊
Long-Term Monitoring
Compare BMI results over weeks, months, or years.
Get More From It

Tips for Using This Calculator

Measure Height Accurately

Stand barefoot against a wall and measure your height carefully for the most accurate BMI calculation.

Use Your Current Weight

Weigh yourself at the same time of day, preferably in the morning, to keep your BMI results consistent.

Log Progress Regularly

Track your BMI weekly or monthly instead of daily to identify meaningful long-term trends.

Use Child Mode for Under 20

Children and teens should use age- and sex-specific BMI percentiles instead of adult BMI categories.

Don't Rely on BMI Alone

Combine BMI with waist circumference, body fat percentage, and lifestyle factors for a more complete health assessment.

Consult a Healthcare Professional

If your BMI falls outside the healthy range or you have health concerns, seek personalized medical advice.

Questions

Frequently Asked Questions

For adults, a BMI between 18.5 and 24.9 is generally considered in the healthy range. For children and teens, healthy BMI is assessed using age- and gender-specific percentiles instead.
Children's body composition changes naturally as they grow, so a fixed BMI number doesn't mean the same thing at every age — percentile comparison against same-age, same-gender peers is more meaningful.
Not always — BMI doesn't distinguish muscle mass from fat mass, so athletes and bodybuilders often show an "overweight" BMI despite having low body fat.
After calculating your BMI, click "Add Current Result to Log" to save that entry with today's date. Each new entry shows a trend arrow comparing it to your previous entry.
No, the log is kept only in your browser for the current session and is not sent to or stored on our servers. Refreshing the page will clear it.
BMI = weight in kilograms divided by height in metres squared. See our Formula section above for the full breakdown and worked example.
Yes — factors like fat distribution, muscle mass, age, and overall fitness all affect health risk independently of BMI, which is why it's best used as a screening tool rather than a diagnosis.
It's a reasonable approximation based on average growth patterns, but official clinical assessment uses detailed growth charts (such as CDC or WHO references) — consult a pediatrician for a precise reading.
Consider it a starting point for a conversation with a doctor or dietitian rather than a diagnosis — they can assess your full health picture, not just one number.
The adult BMI formula and categories are the same for both genders, though average body fat percentage at a given BMI tends to differ between men and women.
Yes, use the unit toggle above the calculator to switch between centimetres/kilograms and feet-inches/pounds at any time.
BMI depends on both height and weight — if you re-measure your height slightly differently, or if a child's height has grown since the last entry, the calculated BMI will shift accordingly.
Standard BMI categories are not designed for pregnancy, since healthy weight gain is expected and assessed differently — consult your doctor for pregnancy-specific weight guidance.
No. All calculations, including your Body Metrics Log, run entirely in your browser for this session — nothing is sent to or stored on our servers.
Ages 2 to 19, consistent with standard pediatric BMI-for-age growth chart ranges. For children under 2, growth is typically assessed using weight-for-length charts instead.

Know Your Numbers, Track Your Progress

Calculate your BMI above, then start logging your journey with the Body Metrics Log.

✓ Adult & Child Modes ✓ Instant Results ✓ Progress Log