Understanding Your Calorie Needs
This calculator uses the Mifflin-St Jeor equation, considered the most accurate formula for estimating Basal Metabolic Rate (BMR) for most adults. BMR represents the number of calories your body burns at complete rest just to maintain basic functions like breathing, circulation, and cell production.
The Mifflin-St Jeor Equation
Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
Your BMR is then multiplied by an activity factor to get your Total Daily Energy Expenditure (TDEE). To lose weight, eat 500 calories below TDEE for roughly 1 pound per week loss. To gain weight, eat 500 calories above TDEE.
Tips for Using Your Results
These calorie targets are estimates and may need adjustment based on your metabolism, medical conditions, and specific goals. Track your actual intake and weight changes over 2-3 weeks and adjust accordingly. A registered dietitian can help you fine-tune your nutrition plan for optimal results.
Frequently Asked Questions
What is the Mifflin-St Jeor equation?
The Mifflin-St Jeor equation is a formula developed in 1990 that estimates your Basal Metabolic Rate (BMR) based on weight, height, age, and gender. It is considered more accurate than the older Harris-Benedict equation for most people.
What is TDEE?
TDEE stands for Total Daily Energy Expenditure. It is your BMR multiplied by an activity factor and represents the total number of calories you burn in a day including exercise and daily activities.
How many calories should I eat to lose weight?
A deficit of 500 calories per day below your TDEE typically results in about 1 pound of weight loss per week. Avoid going below 1200 calories (women) or 1500 calories (men) per day without medical supervision.
Why does activity level matter so much?
Activity level can add 20% to 90% more calories on top of your BMR. A very active person might need 1000+ more daily calories than a sedentary person of the same size and age.
How accurate is this calculator?
The Mifflin-St Jeor equation is accurate to within about 10% for most adults. Individual factors like genetics, body composition, and medical conditions can cause variations. Use it as a starting point and adjust based on real results.