Calorie Calculator
Estimate your daily calorie needs from your age, height, weight and activity level, with targets for maintaining, losing and gaining weight.
How your daily calories are worked out
There are two numbers that matter. Your BMR is what your body burns doing nothing at all - the energy that keeps your heart beating and your temperature steady. Your TDEE is that figure scaled up for how active you are, and it is the amount you would eat to hold your weight exactly where it is. Everything else, losing or gaining, is a nudge either side of that.
The Mifflin-St Jeor equation
This calculator uses the Mifflin-St Jeor formula, the one most dietitians reach for because it
tracks modern bodies better than the older Harris-Benedict version. For a man it is
10 x weight(kg) + 6.25 x height(cm) - 5 x age + 5; for a woman the final term is
- 161 instead of + 5. A 30-year-old man at 175 cm and 70 kg gets a
BMR of 1,649. Multiply by 1.375 for a lightly active week and his maintenance need is about
2,267 calories a day.
Turning it into a plan
To lose weight, eat below maintenance. A 500-calorie daily deficit sheds roughly half a kilo (about a pound) a week, because a pound of fat holds around 3,500 calories. To gain in a controlled way, a 300-calorie surplus adds muscle without much extra fat if you train. The grid above shows all four targets at once so you can pick the one that fits your goal.
Treat it as a starting point
These are estimates. Metabolisms vary by 5 to 10 percent either way, and the activity multipliers are broad brush. Use the maintenance figure for a fortnight, weigh yourself, and adjust by 100 to 200 calories if the scale is not moving the way you expected. Check where your weight sits with the BMI calculator, and if you are tracking a target date, the percentage calculator makes progress easy to follow.