Health

The BMI calculator shows where your weight falls in the adult categories used by the CDC and WHO. BMI is a quick screen, but it can't tell muscle from fat, so it's worth also checking your body fat percentage and waist-to-hip ratio, which says more about the health risk of belly fat. The ideal weight calculator gives a healthy range for your height along with four classic formulas.

For ages 2 to 20, adult cut-offs don't apply: the BMI calculator for kids uses CDC growth charts to give a percentile, and for severe obesity, a percentage of the 95th percentile. We never give a child a weight-loss target; that's a decision to make with your pediatrician.

The calorie calculator estimates your BMR with three formulas (Mifflin–St Jeor, revised Harris–Benedict and Katch–McArdle) and shows your TDEE at all five activity levels, each defined in minutes. After 2 to 4 weeks you can refine it with your own intake and weight change. To lose weight, the calorie deficit calculator gives you a goal date and a weekly plan, and it never suggests eating below the safe minimum: 1,200 calories for women, 1,500 for men, and never below your BMR.

The macro calculator and protein calculator show ranges based on international guidelines, while the calorie chart and glycemic index chart help you choose foods.

The WHO and the US Physical Activity Guidelines recommend 150 to 300 minutes of moderate or 75 to 150 minutes of vigorous activity a week for adults, plus muscle strengthening on two or more days. The heart rate zone calculator works out training zones from your maximum and resting heart rate, and the pace calculator converts between pace, time and distance for runs.

For strength training, the one rep max calculator estimates your 1RM with three formulas and gives you percentage-based training weights and a plate loader. The calories burned calculator uses the original MET values of nearly 200 activities from the 2024 Compendium of Physical Activities and shows both gross and net calories.

So you don't have to retype your details in every calculator, you can save your sex, age, height and weight in the My profile bar. It's stored only in this browser on this device (localStorage), never sent to our servers, and one button deletes it. Our other health calculators then open with your details filled in.

The Copy link to this result button puts your inputs into the link so you can bookmark the result or send it, for example to your coach or dietitian. Your values only go into the address bar when you press the button, and only people you send the link to can see them.

Every health tool page lists at least two primary sources: guidance from organizations like the WHO, CDC, NIH and FAO, and the original peer-reviewed papers behind each formula. Our new and updated calculators also have a methodology box explaining the formula and data we use, how we tested it and what the tool can't tell you. We check formulas against known test cases, automatically for our new calculators before every release, and every page shows when it was last reviewed.

Reviews are currently done by our editorial team; we don't list a named doctor or dietitian as reviewer, because we don't have one yet. The tools are for information only, don't diagnose anything and don't replace your doctor or a registered dietitian. Our editorial policy explains how we work and how to report a mistake.

Numbers help you get your bearings, but they don't diagnose anything. Talk to your doctor if you're losing weight without trying (more than 5% of your body weight in six months), if your blood pressure is 130/80 mmHg or higher on repeated readings, if you get chest pain, unusual shortness of breath or dizziness during exercise, or if you have diabetes, heart disease or kidney disease and plan to change your diet or training. Dieting during pregnancy or breastfeeding, or for children and teens, is always a question for a doctor or registered dietitian. And if thoughts about food, weight or exercise are causing you distress, that's a good reason to reach out for help too.