Health
How Many Calories Should You Eat to Lose Weight?
Find your maintenance calories, then subtract a sensible deficit. A 500-calorie daily cut is about one pound a week.
Health calculators
Know your numbers with science-backed formulas
BMI, calories, metabolism, and body composition — estimated with the same validated equations clinicians and trainers use, in plain, private, instant tools.
Body metrics
BMI and body-fat percentage with the category ranges to interpret them.
Metabolism
BMR and total daily energy expenditure via the Mifflin-St Jeor equation.
Nutrition targets
Calorie goals for maintaining, losing, or gaining at a healthy pace.
The tools
4 health calculators
From measurements to a plan
Whether you're setting a calorie target, tracking a fitness goal, or just curious where you stand, it helps to start from real numbers. These health calculators use established formulas — Mifflin-St Jeor for metabolism, the U.S. Navy method for body fat, WHO ranges for BMI — to turn your stats into useful estimates.
They're screening and planning tools, not diagnoses. Body composition, genetics, and activity all affect what's right for you, so treat the outputs as a starting point and track real-world results over a few weeks. Everything is calculated in your browser and never stored.
Pair the calculators with the guides below to understand what the numbers mean, where the formulas fall short, and how to turn an estimate into an actual nutrition or training plan.
Guides
Read up on health
Health
How to Calculate Your Daily Calorie Needs (TDEE)
Your TDEE is the calories you burn in a day. Here's how the Mifflin-St Jeor equation and an activity factor estimate it.
Health
BMI vs. Body Fat Percentage: Which Should You Track?
BMI is a quick screen from height and weight; body fat percentage measures composition. Here's when each is useful.
Frequently asked questions
- Are these health calculators accurate?
They use clinically validated formulas and are accurate for most people as estimates. They don't replace medical advice — talk to a doctor before making big changes.
- Why do BMI and body fat sometimes disagree?
BMI only uses height and weight, so muscular people can read high. Body-fat percentage measures composition directly and is usually the better indicator of fitness.
- Is my data private?
Yes. Nothing you enter leaves your device — the calculators run entirely in your browser.