How your daily calories are calculated
The calculator first estimates your Basal Metabolic Rate (BMR) with the Mifflin-St Jeor equation, which research shows is the most reliable of the common formulas. It then multiplies BMR by an activity factor from 1.2 (desk job, no exercise) up to 1.9 (very hard daily training) to get maintenance calories.
From maintenance it applies your goal: about 20% fewer calories to lose fat, about 10% more to gain muscle, or maintenance to stay put.
Choose the honest activity level
Most people overestimate activity. If you sit most of the day and train 3 to 4 times a week, "lightly active" is usually closer to the truth than "very active". Start there, follow the target for two to three weeks and check the scale trend.
Do not go too low
Eating far below your maintenance level costs muscle, energy and sleep. As a rule of thumb do not go under about 1,200 kcal (women) or 1,500 kcal (men) without medical supervision. For the next step after this number, use the macro calculator to split it into protein, carbs and fat.
Frequently asked questions
How many calories should I eat to lose weight?
A deficit of 15–20% below maintenance is a sustainable starting point, which usually means losing around 0.25–0.75 kg (0.5–1.5 lb) per week.
Is the calorie calculator accurate?
It is a good estimate, typically within about 10% of your real needs. Treat the first two weeks as calibration and adjust based on your weight trend.
Are calories the same as kcal?
Yes. In nutrition, "calorie" almost always means kilocalorie (kcal), the number printed on food labels.
Results are estimates for general information and are not medical advice. See our disclaimer. Talk to a doctor or registered dietitian before making major changes to your diet or training.