BMI Calculator
Estimate body mass index from weight and height using the standard BMI formula.
Check your units with a worked example
For an adult weighing 70 kg and measuring 1.75 m, BMI = 70 ÷ (1.75 × 1.75) = 22.86, usually displayed as about 22.9. If height is recorded as 175 cm, convert it to 1.75 m before squaring it. Using centimetres directly in a formula that expects metres changes the result by a factor of 10,000.
Adult BMI and child BMI are interpreted differently
For adults, BMI is one screening measure based on height and weight. The CDC adult BMI calculator provides adult context, but the number alone does not diagnose a condition. For children and teens ages 2 through 19, CDC uses age- and sex-specific BMI-for-age percentiles because growth changes how the result is interpreted. The CDC child and teen BMI calculator is one official reference. Do not apply adult BMI cutoffs to a child or teenager; use an appropriate pediatric reference and qualified clinical guidance.
What this number cannot tell you
BMI does not directly measure body fat or show where fat is distributed. It cannot distinguish muscle from fat or bone, and it does not account for symptoms, medical history, pregnancy or every factor that affects a person's health. Two people with the same BMI can have different body composition and health circumstances. Treat this page as a mathematical screening aid, not a diagnosis or a treatment recommendation.
For background on the measure and its limits, see the CDC explanation of BMI. For personal concerns or decisions about diet, exercise or treatment, discuss the result with a qualified healthcare professional.
Related resources
How to interpret a BMI result
Body mass index is a screening calculation based on weight divided by height squared. It offers a quick way to compare a person's weight relative to their height, but it does not directly measure body fat, muscle, body composition or overall health. A result should be interpreted in context rather than treated as a diagnosis or a complete picture of physical wellbeing.
Enter consistent measurements
- Measure weight and height using the units the calculator requests.
- Check the decimal point and unit labels before calculating.
- Read the result together with the stated interpretation and age limitations.
- If tracking a change over time, use the same measurement method and similar conditions.
For example, entering height in inches where centimetres are expected can produce a severely misleading result. If a value seems unusual, verify the measurements before drawing a conclusion. BMI interpretation for children and teenagers uses age- and sex-specific percentiles, so an adult BMI range should not be applied to a child as though it were a clinical assessment.
Health limitations
The calculator is a general mathematical aid and does not consider pregnancy, muscularity, fluid retention, medical history or individual risk factors. A person's health cannot be assessed from one number. For concerns about weight, nutrition or medical conditions, seek guidance from a qualified health professional who can consider the broader clinical context.
BMI questions
Does BMI measure body fat directly?
No. It is calculated from height and weight and does not distinguish muscle from fat.
Can I use adult BMI ranges for a child?
No. Children and teenagers need age- and sex-specific interpretation from an appropriate health source.
When to seek an individual interpretation
If a BMI result worries you or conflicts with how you feel, do not use a web calculator alone to decide what it means for your health. A clinician can consider your age, medical history, body composition, activity, medication and other measurements that this simple formula does not capture. Keep the result in perspective and use it as a prompt for an informed discussion rather than a diagnosis.
How to use BMI Calculator for everyday work and study
BMI Calculator is designed for freelancers estimating project hours, remote workers checking a quick business number, and students validating coursework before submitting it. For BMI Calculator, the real benefit comes from applying the output correctly, not merely seeing a number or transformed value. For BMI Calculator, enter source information carefully, then read the output in light of the assumptions that produced it. Use BMI Calculator as a focused browser step when a quick check would otherwise mean setting up a separate spreadsheet.
Worked example: BMI Calculator
Enter height and weight in matching units, then verify the conversion before interpreting the number. BMI is a screening measure rather than a direct measurement of body fat or individual health; age, pregnancy, muscle mass, and clinical context change what the result means. Discuss personal concerns with a qualified clinician.
Start with the inputs, not the answer
Before running BMI Calculator, review the fields it actually uses, such as dates, units, text, quantities, or settings. A freelancer using BMI Calculator can document a quote, invoice, proposal, delivery estimate, or other client-facing result with the inputs that produced it. For a remote team, BMI Calculator can help inspect the input before it is translated into the team's agreed format or workflow. After completing the underlying work, students can use BMI Calculator to check one specific part of the answer without replacing their own reasoning. For BMI Calculator, an incorrect source value can still produce a misleading output, so review the original fields before relying on the result.
A practical US workflow
When a US freelancer uses BMI Calculator, retaining the source value beside the output makes the check easier to explain later. For BMI Calculator, note its relevant input, such as an amount, duration, text sample, unit, or setting, next to the output that the page returns. A remote teammate can document how BMI Calculator was used in a project ticket, letting colleagues repeat the same steps. For coursework, BMI Calculator works best alongside the original exercise: compare both to catch arithmetic, formatting, or conversion mistakes without skipping the learning step. Keeping the inputs with BMI Calculator's output gives a client or teammate a trail to review instead of a number with no explanation.
When the result needs a second check
If BMI Calculator is used for a contract, tax return, payroll choice, school requirement, or another consequential task, verify the result independently before relying on it. BMI Calculator can speed up a routine calculation or transformation, but it cannot infer special project assumptions or know every change made by an outside authority. Before acting on BMI Calculator's result, check its inputs, reproduce important figures independently, and ask the responsible organization about official requirements. BMI Calculator is a practical utility, not a substitute for professional advice or an official record.
Tips for repeat use
- For BMI Calculator, choose a unit and rounding convention and apply it consistently across the task.
- Save the inputs used by BMI Calculator alongside its output whenever a client or teammate may ask how the result was reached.
- Only provide BMI Calculator with information required for its task; leave out client secrets and unrelated confidential details.
- When sending a BMI Calculator result to a client, label estimates clearly and state the assumptions that matter.
- For an assignment involving BMI Calculator, follow the instructor's rules about permitted calculators, outside assistance, and submitted work.
Limitations and privacy
What BMI Calculator returns depends on the information supplied and the method implemented on this page. BMI Calculator may not cover every unusual input, local requirement, product-specific convention, or future change. If BMI Calculator displays live or external data, check the stated source and timestamp instead of assuming the value stays current. For sensitive work, use the minimum information necessary. The best way to use BMI Calculator is to understand the assumptions and verify consequential outputs rather than treating convenience as official authority.
Page-specific reference: BMI Calculator. This guide explains practical cases for BMI Calculator, including the points where its result needs independent confirmation.
Frequently asked questions about BMI Calculator
What is BMI Calculator used for?
BMI Calculator helps complete the specific task represented by its fields and output. Use BMI Calculator as a routine check, then confirm that its output matches the real-world task and assumptions you intended to evaluate.
Can freelancers use BMI Calculator for client work?
A freelancer can use BMI Calculator while preparing routine client work, but any quoted amount, converted asset, or consequential output should be checked against the client's assumptions before delivery.
Can students use BMI Calculator?
A student can use BMI Calculator to check a worked attempt when course rules permit outside tools. When using BMI Calculator for coursework, students should show their own reasoning and comply with the instructor's submission requirements.
Is the result an official or professional determination?
No. The output from BMI Calculator is informational, not an official determination. For consequential use of BMI Calculator, confirm regulated decisions, formal requirements, and professional advice with the appropriate authority or qualified professional.
What should I do if the result looks wrong?
If BMI Calculator produces an unexpected result, check its inputs, units, dates, and rounding settings. For an important BMI Calculator result, reproduce the output independently and compare methods before relying on it.