Calorie Calculator

How it works

First we estimate your basal metabolic rate (BMR) — the energy you burn at rest — with the Mifflin-St Jeor equation, which research has found to be among the most accurate predictive equations for healthy adults:

Men: BMR = 10 × kg + 6.25 × cm − 5 × age + 5
Women: BMR = 10 × kg + 6.25 × cm − 5 × age − 161

Then we multiply BMR by an activity factor to estimate your total daily energy expenditure (TDEE), or maintenance calories:

Finally we add or subtract 250 or 500 calories a day. A 500-calorie daily deficit is the traditional guide for losing about 1 lb (0.45 kg) a week, though real-world loss is usually slower over time as the body adapts.

Safety minimums

Very low intakes make it hard to get enough protein, vitamins and minerals and should be supervised by a professional. This calculator never suggests fewer than 1,200 calories a day for women or 1,500 for men. If a deficit would go below that, the target is raised to the minimum, marked with an asterisk, and a warning is shown. If you see the warning, please talk to a doctor or registered dietitian before cutting further.

Choosing a target

Slower is usually more sustainable: the 250-calorie "mild" options mean about half a pound a week. For a goal date based on your target weight, try the Calorie Deficit & Goal Date Calculator, and to turn calories into protein, carbs and fat, use the Macro Calculator.

Calories vs. food quality

Calorie targets control weight change, but what fills them affects hunger, energy and long-term health. Building meals around vegetables, fruit, whole grains, legumes, lean proteins and unsaturated fats makes a given calorie level more filling and nutrient-dense than the same calories from sugary drinks or ultra-processed snacks.

Worked examples

Example 1: Man, 35, 180 lb, 5′10″, moderately active

81.6 kg, 177.8 cm. BMR = 816.5 + 1,111.3 − 175 + 5 ≈ 1,758 kcal. TDEE = 1,758 × 1.55 ≈ 2,724 kcal. Mild loss ≈ 2,474; loss ≈ 2,224 kcal/day.

Example 2: Woman, 50, 130 lb, 5′3″, sedentary

59.0 kg, 160.0 cm. BMR ≈ 1,179 kcal; TDEE = 1,179 × 1.2 ≈ 1,415 kcal. A 500-calorie deficit would be 915 kcal, so the calculator shows 1,200 kcal* instead, with a safety warning. Adding activity is a safer way to widen the gap.

Example 3: Gaining weight

For the man in Example 1, a mild surplus is 2,724 + 250 ≈ 2,974 kcal/day, aimed at slow gain alongside strength training.

Limitations

• Predictive equations are typically within about ±10% for most healthy adults, but individuals can be further off.
• Activity multipliers are broad; most people overestimate their activity.
• The 3,500-calories-per-pound rule overestimates long-term loss; adjust based on your real progress over 2–4 weeks.

Who should not rely on this calculator

Not for children or teens, pregnant or breastfeeding people, people with a history of eating disorders, or people with medical conditions such as diabetes, kidney disease or thyroid disorders. These groups should get calorie targets from a healthcare professional.