The calculators and articles on whatshouldiweigh.com are educational. They are not medical advice, and they are not a substitute for care from a qualified professional who knows your history.
What this site actually does
Every calculator here applies a published formula to numbers you type in. BMI, resting metabolism, body fat from tape measurements, calorie needs, protein targets — each one is a population-level estimate derived from research on groups of people.
That matters because a population estimate is not a measurement of you. The formulas were built by averaging across large samples, and individuals vary considerably around any average. Two people who enter identical numbers receive identical answers, regardless of build, training history, medical conditions or medication.
We say so on each calculator, and we name the source formula in the footer of each one, so you can look up its limitations yourself.
What this site does not do
- It does not diagnose, treat, cure or prevent any disease or condition.
- It does not tell you what you personally should weigh, eat or do.
- It does not account for your medical history, medication, or anything a clinician would consider.
- It does not replace testing. A calculator cannot rule out a thyroid condition, insulin resistance, or anything else that requires blood work.
No statement on this site has been evaluated by the Food and Drug Administration.
Talk to a doctor before you make changes
Speak with your physician, a registered dietitian, or another qualified provider before changing how you eat, train or supplement. That advice is stronger, not weaker, if any of the following apply:
- You are pregnant, nursing, or trying to conceive
- You are under 18, or over 65
- You have a heart condition, diabetes, kidney or liver disease, or a thyroid disorder
- You take medication affecting appetite, blood sugar, fluid balance or metabolism
- You have a history of disordered eating
- Your weight has changed noticeably without an explanation you understand
That last one is worth repeating. Unexplained weight change is a symptom, and it is one of the more common reasons a treatable condition goes undetected for months. A calculator cannot help with it. A blood test often can.
If tracking is becoming something else
If food, weight or exercise is taking up more of your thoughts than you want, if you find yourself skipping meals to make up for eating, or if a number on a scale sets the tone of your day, that is worth talking to someone about — and it is common.
National Alliance for Eating Disorders Helpline — 1-866-662-1235. Free and confidential, staffed by licensed therapists who specialise in eating disorders, 9:00 am to 7:00 pm ET, Monday to Friday.
That line is not a 24-hour crisis service. If you need someone right now, call or text 988 (Suicide & Crisis Lifeline) or text ALLIANCE to 741-741. Both are free and available 24 hours a day.
An eating disorder can become a physical emergency without any suicidal intent. If you are fainting, experiencing chest pain, an irregular heartbeat, severe dehydration or another potentially serious symptom, call 911 or go to your nearest emergency department.
No calculator on any website, including this one, is equipped to help with this. A person is.
Accuracy and limitations
We take accuracy seriously and cite our sources. We also acknowledge where the evidence disagrees with itself — body composition methods are a good example, where published validation studies reach genuinely different conclusions.
Even so, formulas are revised, guidelines change, and errors are possible. Nothing here is guaranteed to be complete, current or correct. If you spot something wrong, please tell us.
Third-party content
This site links to external resources, and some links are affiliate links, disclosed where they appear. We do not control third-party content and are not responsible for what other sites publish or sell. A link is not an endorsement of everything at the other end of it.
In short: use these calculators to understand the numbers and what they mean. Use a doctor to decide what to do about them.
Emergencies
If you think you may be experiencing a medical emergency, call 911 or your local emergency number immediately. Do not delay seeking medical advice because of something you have read on this site.
Last reviewed: 8-19-2026
Questions about this page: Email: Margot @ whatshouldiweight.com