Know your numbers
Work out your calories, macros, body fat and strength in seconds. Pick a tool below. No sign-up needed.
TDEE calculator
Find out how many calories you burn in a day, plus your BMR, BMI, ideal weight, muscle potential and macros for cutting, maintaining or bulking.
How it works
Your TDEE (total daily energy expenditure) is the number of calories you burn in a full day. First we estimate your BMR, which is what your body burns at complete rest, using the Mifflin-St Jeor equation. Then we multiply it by your activity level.
If you add your body fat percentage, we switch to the Katch-McArdle equation. It works from your lean mass, so it's more accurate for people carrying a lot of muscle.
How to use your number
- To hold your weight, eat around your TDEE.
- To lose fat, eat about 500 calories under it. That's roughly 0.5 kg (1 lb) a week.
- To build muscle, eat 250 to 500 calories over it, and keep your protein high.
- It's a starting point. Weigh yourself for 2 to 3 weeks and adjust by 100 to 200 calories if the scale isn't moving the way you want.
Macro calculator
Get your daily calories, protein, carbs and fat for your goal, split across however many meals you eat.
How it works
We estimate your maintenance calories, then raise or lower them for your goal. Protein is set from your body weight (1.8 to 2.2 g per kg, or 0.8 to 1 g per lb), because it's the macro that matters most for keeping and building muscle.
Fat is set at 25% of your calories to support your hormones, and carbs fill the rest to fuel your training.
Good to know
- Hit protein first. If you only track one thing, track this.
- Carbs and fat can flex. Swapping some between them is fine as long as calories stay close.
- Cut slower if you're lean. The leaner you are, the smaller your deficit should be to protect muscle.
- Protein in one meal: 25 to 50 g is a good target, so spread it across the day.
BMI calculator
Check your body mass index and the healthy weight range for your height.
How it works
BMI is your weight in kilograms divided by your height in metres squared. A BMI of 18.5 to 24.9 is classed as a healthy weight, 25 to 29.9 as overweight and 30 or more as obese.
BMI prime is your BMI divided by 25, the top of the healthy range. Under 1.0 means you're under that limit.
Where BMI falls short
- It can't tell muscle from fat. If you lift, you can score as overweight while being lean.
- It ignores where you carry fat. Waist size says more about your health.
- For a better picture, use the body fat calculator.
Body fat calculator
Estimate your body fat percentage with just a tape measure, using the U.S. Navy method.
How to measure
- Neck: just below your Adam's apple, with the tape sloping slightly down at the front.
- Waist: men, level with your belly button. Women, at the narrowest point.
- Hips (women): around the widest part of your hips and glutes.
- Keep it consistent: bare skin, standing relaxed, no sucking in. First thing in the morning works best.
How accurate is it?
The Navy method is usually within 3 to 4% of lab tests like a DEXA scan, which makes it one of the best home methods. It's most useful for tracking change: measure every 2 to 4 weeks and watch the trend rather than any single result.
One rep max calculator
Estimate the most you could lift for one rep, and get your working weights for every rep range, without testing a true max.
How it works
Enter a weight and the number of clean reps you did with it. We average two well-tested formulas, Epley and Brzycki, to estimate your one rep max.
The estimate is most accurate with a hard set of 2 to 6 reps. Past 10 reps it gets less reliable.
Using your training weights
- Strength: 85 to 100% of your max for 1 to 5 reps.
- Muscle growth: 65 to 85% for 6 to 12 reps. This is where most of your sets should be.
- Endurance: under 65% for 15 reps or more.
- Stay safe: never test a real max without a spotter or safety bars.
Numbers are step one.
Now put them to work. Get the training plan and the science to build muscle the right way.