6 calculators
Health Calculators
Know your numbers, then talk to your doctor
These health calculators give you reference numbers in pounds, feet and inches or metric: your BMI and healthy weight range, the calories you burn, an estimate of body fat, your heart rate zones, your running pace and your due date.
See all 6 calculatorsThe key idea
A number is a starting point, not a diagnosis
A BMI of 26.6 puts a 5 ft 9 in, 180 lb adult in the overweight range, but BMI does not tell muscle from fat. Use these numbers to understand your situation and as a question to bring to your doctor, not as a verdict.
What you can calculate
6 calculators, one for every question
BMI Calculator
Your body mass index and its NHLBI category.
Calculate 02Calorie Calculator
Your resting metabolic rate and the calories you need each day.
Calculate 03Body Fat Calculator
Your body fat percentage with a tape measure.
Calculate 04Target Heart Rate Calculator
Your max heart rate and your 5 training zones.
Calculate 05Pace Calculator
Min/mile, min/km, speed and your 5K to marathon times.
Calculate 06Due Date Calculator
Estimated due date and how many weeks pregnant you are.
CalculateHow we work
How we build calculators, in three principles
Diagnosis
Source first
Every formula comes from the law, the agency or the original study.
If a calculation depends on a rule (federal tax brackets, the Fair Labor Standards Act, Social Security), we start from the official text from the IRS, the Department of Labor or the SSA and link it on the page. If it depends on a study, we cite the study.
No figures copied from another calculator.
Method
Checked by hand
Every calculator is tested against cases worked out by hand.
The example on each page is one of those cases and matches the tool to the cent. We also test the edge cases: zeros, negatives, legal caps and odd dates.
When a rule changes, we review it and log the change on our corrections page.
Tool
Built to be understood
The result comes with the formula, the example and the common questions.
Everything runs in your browser, instantly and with no sign-up. You can share a calculation with a link, save it to your history or download it to Excel.
We do not store what you type.
Common questions
Frequently asked questions
What is a healthy BMI?
For adults, 18.5 to 24.9, according to the NIH National Heart, Lung, and Blood Institute. Below 18.5 is underweight, 25 to 29.9 overweight and 30 or more obesity.
How many calories do I need a day?
It depends on your sex, age, weight, height and activity. The calorie calculator estimates it with the Mifflin-St Jeor equation: about 2,556 a day for a moderately active 30-year-old man of 154 lb and 5 ft 9 in.
How is a due date calculated?
By adding 280 days, 40 weeks, to the first day of your last menstrual period. An early ultrasound can adjust it; your doctor or midwife gives the official date.
Can I use pounds and inches?
Yes: every calculator uses US units by default, and the ones that need it also accept kilograms and centimeters.
Are the results medical advice?
No. They are estimates from standard formulas for adults. For any health decision, talk to a doctor or another qualified health professional.
Is my data saved?
No. Your weight, height and dates stay in your browser and are not sent anywhere.
Other categories
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