Pick a tool
BMI Calculator
Body mass index from weight & height
Body Fat Calculator
Estimate fat percentage using the US Navy method
Ideal Weight
Ideal body weight for your height
Lean Body Mass
Your weight minus all body fat
Waist-to-Height Ratio
A more reliable risk indicator than BMI alone
Waist-to-Hip Ratio
Cardiovascular risk assessment
BMI Prime
Ratio to upper healthy weight limit
Army Body Fat
US Army circumference method
TDEE Calculator
How many calories you actually burn per day
Macro Calculator
Protein, carbs & fat targets for your goal
Water Intake
Daily hydration estimate by weight
Calorie Deficit
Calories to eat for weight loss
Calorie Surplus
Calories for muscle gain
Protein Intake
Daily protein target — most people eat too little
Fat Intake
Daily fat grams from your calorie target
Carbohydrate Intake
Daily carb target by diet style
Resting Metabolic Rate
Calories burned at complete rest (Mifflin-St Jeor)
Exercise Calorie Burn
Calories burned per workout
Fibre Intake
Daily fibre by age and sex
Alcohol Units
Units and calories in drinks
Heart Rate Zones
5 training zones from your max HR
One Rep Max (1RM)
Max strength from any lift (Brzycki formula)
VO2 Max Estimator
Cardiovascular fitness score
Running Pace
Pace from distance and time
Steps to Calories
Calories burned from steps
Push-Up Fitness Test
Rate your push-up performance by age
Pace to Speed
Convert pace to km/h or mph
Age Calculator
Exact age in years, months & days
Percentage Calculator
Quick percentage math
Sleep Calculator
Best wake times based on sleep cycles
Pregnancy Weight Gain
Recommended gain by pre-pregnancy BMI
Due Date Calculator
Estimated delivery date
Body Surface Area
Used in medical dosing calculations
Health reads
What is BMI — and When Should You Actually Care?
BMI is flawed, overused, and still the fastest rough indicator you've got. Here's what it actually tells you.
Read guide →How to Lose Weight — No Supplements Required
No shortcuts. Just the calorie math that actually works, explained plainly.
Read →How to Build Muscle — Nutrition Fundamentals
Protein, calories and the science of hypertrophy without the bro-science.
Read →How Many Calories Should You Actually Eat?
The answer depends on more than just your weight. Here's how to find your real number.
Read →Understanding Macronutrients
Protein, carbs and fats — what they actually do, and why the ratio matters.
Read →Heart Rate Training Zones Explained
Most people train in the wrong zone. Here's how to fix that.
Read →How Much Protein Do You Need?
Most people eat too little. Here's the actual number, based on your goal.
Read →Daily Water Intake — The Real Answer
"8 glasses a day" isn't based on much. Here's what actually makes sense for your body.
Read →Healthy Body Fat Percentage
Ranges, what they mean, and why body fat tells a different story than BMI.
Read →How Much Sleep Do You Actually Need?
Sleep is probably doing more for your fitness than your workout. Here's why.
Read →I built the tool I couldn't find
I wanted a quick BMI check. Every site I landed on wanted an email address, showed five popups, or buried the result under ads. So I built a clean one. Then someone asked for TDEE. Then macros. Now there are 36 calculators — all free, all instant, no account needed.
Formulas are sourced from established research — BMI uses the standard kg/m² formula, BMR uses Mifflin-St Jeor, body fat uses the US Navy circumference method, and 1RM uses Brzycki. Nothing proprietary, nothing made up.