BMI calculator

Calculate your BMI and see the healthy weight range.

Last updated: January 8, 2026

Built and maintained by Aaron Jegla

Reviewed against CDC and NIH public guidelines. Not clinically reviewed.

For adults age 20+. Children and teens should use BMI-for-age percentiles. Use metric or imperial inputs to get your BMI, category, and weight range. The chart adapts for mobile so you can read it without side-scrolling.

BMI inputs

Switch units and we will convert your inputs automatically.

Enter feet and inches from your height.

Use your current weight without shoes or heavy clothing.

Adult BMI categories apply to age 20+. Ages 2-19 use percentiles.

For adults age 20+. The chart uses adult categories for screening only.

Not for kids, teens, or pregnancy-specific assessments. Explore our health calculators.

How to use this calculator
  1. Select imperial or metric and enter your height and weight.
  2. Add your age if you want the adult vs teen reminder.
  3. Click Calculate to see your BMI, category, and chart.

Use consistent measurements to compare results over time.

Summary

Adult BMI categories are screening tools, not medical diagnoses.

Your BMI

0

Category

--

Healthy weight range

--

Change to reach healthy range

--

At your height, BMI 25 starts at --.

Sources: CDC BMI overview, CDC adult BMI categories, NHLBI BMI classification chart

Assumptions: Adult BMI categories (age 20+) and standard height/weight measurements. BMI does not account for muscle mass, body composition, or pregnancy.

Disclaimer: Estimates only and not medical advice. Use BMI as a screening tool and discuss results with a healthcare professional.

Interactive BMI chart

Color bands show the standard adult BMI categories. Your point updates with each calculation.

Underweight Healthy Overweight Obesity

Use Focused mode on mobile for larger labels and fewer tick marks.

Category BMI range Weight range

Ranges shown for your current height.

How this calculator works

BMI uses weight and height only. It does not estimate body fat directly.

Metric formula:

BMI = weight (kg) / height (m)^2

Imperial formula:

BMI = 703 * weight (lb) / height (in)^2

This calculator converts units behind the scenes so both methods match the same BMI value.

BMI insights and common misses

Use these notes to interpret the number with more context.

Screening, not diagnosis

BMI is a fast screening tool. It does not measure body fat or overall health on its own.

  • Use it to start a conversation, not to self-diagnose.
  • Pair it with other checks like blood pressure or labs.

Muscle mass can skew BMI

Athletes or people with higher muscle mass can read as overweight even with low body fat.

  • Compare BMI with waist size and how you feel.
  • Body composition scans provide more detail.

Age and life stage matter

Adult BMI categories apply to age 20+. Kids and teens need percentiles.

  • Pregnancy changes weight patterns; BMI is not designed for it.
  • Older adults may have different healthy ranges.

Measurement quality counts

Small changes in height or weight can shift the BMI category.

  • Measure height without shoes on a flat surface.
  • Weigh yourself at similar times of day.

Healthy range is a span

There is no single "perfect" weight. The healthy range spans more than one number.

  • Use the range to set realistic targets.
  • Focus on trends instead of single-day results.

Next steps

If your BMI is outside the healthy range, this may be a prompt to discuss habits or goals with a healthcare professional.

  • Start with sustainable habits, not extremes.
  • Ask a clinician if you need a personalized plan.

BMI calculator FAQs

Click a question to expand the answer.

What is a healthy BMI range for adults?

For adults age 20+, a BMI from 18.5 to 24.9 is considered the healthy weight range. This is a screening guideline, not a diagnosis.

Is BMI accurate if I have a lot of muscle?

BMI does not separate fat from muscle. People with higher muscle mass can fall into a higher BMI category even if body fat is low.

Can kids and teens use this calculator?

Children and teens use BMI-for-age percentiles instead of adult categories. Use the CDC child/teen BMI calculator for ages 2-19.

Why is my BMI different from the doctor's office?

Small differences in height, clothing, time of day, or rounding can change the result slightly. Use consistent measurements for the best comparison.

What weight puts me in the healthy range?

The healthy weight range depends on your height. This calculator shows the exact weight range and how much you would need to gain or lose to reach it.

Does BMI change by sex?

The adult BMI categories are the same for men and women, but body fat distribution can differ, which is one reason BMI should be interpreted with context.

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