The Forbes Health Calorie Calculator estimates the number of calories your body uses each day. If you want to lose weight, it calculates the number of daily calories you need to consume to achieve your weight loss goal. It also displays how long it will take you to reach your goal weight safely.
Calculating Daily Calories To Maintain Weight
To calculate your daily calorie needs to maintain your weight, the calculator considers your:
- Resting metabolic rate (RMR)
- Physical activity
- The thermogenic effect of food (the calories you burn while processing food)
Each of these components requires a different amount of calories.
1. Your RMR requires the most energy, far more than physical activity or food processing. It can be measured scientifically in a lab or estimated using an equation. In this calculator, your RMR is measured using the Mifflin-St Jeor equation. It’s the most reliable formula, according to a review of studies in the Journal of the American Dietetic Association. It calculates your RMR based on your sex, weight, height and age.
2. Physical activity burns calories, so athletes need to consume more calories than people who don’t exercise. An activity factor—ranging from 1.2 for people who are sedentary to 1.9 for extremely active people—is assigned based on your physical activity level. The calculator then multiplies your RMR by this number.
3. The thermogenic effect of food makes up the remainder of your daily energy needs (approximately 10%). To find this number, the calculator takes your RMR multiplied by your activity factor and multiplies that number by 10%.
Calculating Daily Calories To Lose Weight
To determine your daily calorie needs to lose weight, the calculator decreases the number of calories you use each day by 25%, resulting in a new recommended daily calorie intake. Our Forbes Health Calorie Calculator panel of experts recommended this equation for safe, sustainable weight loss.
The calculator won’t display fewer than 1,200 calories a day no matter your starting weight. “If you go below that, it’s very difficult to get all the macronutrients and micronutrients you need for optimal health,” says Melina Jampolis, M.D., a Forbes Health Advisory Board member.
The Forbes Health editorial team consulted Forbes Health Advisory Board members Melina Jampolis, M.D., Toby Amidor, R.D. and Sabrena Jo, M.S., the senior director of science and research at the American Council on Exercise (ACE), for this calculator. They reviewed the methods used by this tool to calculate daily calorie needs to maintain and lose weight.