Health & Fitness
BMI, calories, macros and other body and wellbeing measures.
Body measurements, energy needs, and cycle and activity tracking. These are the calculators people return to most often, and also the ones where the answer deserves the most caution.
Every formula here was derived from population studies. It describes what is typical for people who share your inputs, which is useful for setting a starting point and poor at describing any particular body.
18 calculators in this category
BMI Calculator
Calculate your Body Mass Index and track your health.
Calorie Calculator
Calculate your daily calorie needs based on age, weight, and activity.
Body Fat Calculator
Estimate body fat percentage using the Navy body fat formula.
Ideal Weight Calculator
Find your ideal body weight range based on height and gender.
Pregnancy Due Date Calculator
Calculate your estimated due date and pregnancy milestones.
BMR Calculator
Basal Metabolic Rate — calories burned at rest (Mifflin-St Jeor).
TDEE Calculator
Total Daily Energy Expenditure with macro breakdown.
Macro Calculator
Calculate protein, fat, and carb targets from calorie goal.
Water Intake Calculator
Daily water recommendation based on weight, activity, and climate.
Sleep Calculator
Find best sleep/wake times based on 90-minute sleep cycles.
Blood Pressure Calculator
Classify blood pressure using AHA 2017 guidelines.
Calories Burned Calculator
Estimate calories burned for 30+ activities using MET values.
Pace Calculator
Running pace, speed, time, and split calculator.
Ovulation Calculator
Find fertile window and estimated ovulation date.
Period Calculator
Predict upcoming periods and ovulation dates.
BAC Calculator
Estimate Blood Alcohol Content using the Widmark formula.
Dog Age Calculator
Convert your dog's age to human years (size-adjusted).
Carbon Footprint Calculator
Estimate your annual CO₂ emissions from driving, flights, energy, and diet.
Which calculator do I need?
Start from the job rather than the tool.
- Check where your weight sits on the standard scale — BMI Calculator or Ideal Weight Calculator
- Work out how much you should be eating — TDEE Calculator or Calorie Calculator or BMR CalculatorBMR is at rest; TDEE adds your activity.
- Split those calories into protein, carbs and fat — Macro Calculator
- Estimate body composition rather than just weight — Body Fat Calculator
- See what an activity burned — Calories Burned Calculator
- Plan a run — Pace Calculator
- Track a cycle or plan around one — Period Calculator or Ovulation Calculator
- Work out a due date — Pregnancy Due Date Calculator
- Interpret a blood pressure reading — Blood Pressure Calculator
- Plan sleep around wake time — Sleep Calculator
- Check daily water intake — Water Intake Calculator
What these calculators have in common
Assumptions worth knowing before you rely on any result here.
These are estimates, not measurements
BMR formulas carry an error of roughly ±10% for any individual, and body fat estimates from tape measurements are wider still. Use the number as a starting point, then adjust based on what actually happens over two or three weeks.
The figures move as your body changes
A smaller body burns fewer calories at rest, so a target set at your starting weight overstates your needs later. Recalculate every few kilograms rather than working from the original figure for months.
Standard thresholds do not fit every population
Many health bodies use lower BMI cut-offs for South Asian and East Asian populations, because metabolic risk appears at a lower value. Ask a clinician which thresholds apply to you.
None of this replaces a clinician
These tools cannot see your history, medication or symptoms. Anything that concerns you, or any result that seems inconsistent with how you feel, is worth raising with a professional rather than resolving here.