Calorie Calculator

A Calorie Calculator estimates daily energy needs from body measurements, a resting energy formula, an activity multiplier, and a selected goal. It is meant to organize planning numbers, not to prescribe a diet.

1. Choose Metric, US, or Other Units.
2. Enter age, formula sex coefficient, height, and weight.
3. Select a BMR method, activity level, and goal.
4. Add body fat percentage only if using Katch-McArdle.
5. Review warnings before using the result for planning.

Daily calorie needs are not a fixed personal number. They change with body size, activity, training, recovery, sleep, health status, and body-weight changes over time.

BMR estimates the calories your body uses at rest for essential functions. For a formula-focused view, use the BMR Calculator.

Activity factors multiply BMR to estimate maintenance calories. They are broad assumptions. A desk job with regular workouts can differ from a physically active job with the same exercise schedule.

Goal adjustments apply a percentage to estimated maintenance calories. A deficit lowers the target, and a surplus raises it. These percentages do not guarantee a precise weekly weight change.

The calculator supports Mifflin-St Jeor, Revised Harris-Benedict, and Katch-McArdle. Mifflin-St Jeor is the default. Katch-McArdle requires body fat percentage because it estimates from lean body mass.

Maintenance calories estimate the intake that would broadly maintain body weight if activity, body size, and tracking accuracy stayed similar. Real needs can change as weight and activity change.

A calorie deficit is an intake target below estimated maintenance. Larger deficits can increase fatigue, hunger, and planning risk, so aggressive targets are flagged rather than recommended.

A calorie surplus is an intake target above estimated maintenance. It may be used for weight-gain planning, but outcomes vary with training, sleep, genetics, and consistency.

The BMR Calculator focuses on resting energy equations. This page uses BMR as one step, then adds activity and goal adjustments.

This calculator gives practical target scenarios. The TDEE Calculator focuses more deeply on activity-based expenditure and maintenance energy.

Nutrition labels commonly use Calories to mean kilocalories. On this page, kcal/day and calories/day refer to that same nutrition unit. Kilojoules are shown as an energy conversion.

Calorie estimates can support planning, but food-label values, tracking, water shifts, appetite, and changing body weight can all affect real-world results.

Equations cannot measure hormones, medical conditions, medication, training history, digestion, exact movement, or metabolic adaptation. Indirect calorimetry and professional assessment can provide more individualized information.

Children and teens have changing energy needs because of growth and development. This calculator allows a general maintenance estimate from age 10, but disables weight-change targets for users under 18.

Pregnancy needs vary by trimester and individual medical context. This calculator shows broad additional-energy context and disables deficit goals when pregnancy is selected.

Breastfeeding energy needs vary with milk production, recovery, activity, and individual health. This calculator shows a general range and disables weight-loss targets.

Estimates may be less accurate for athletes, highly muscular users, users with obesity, older adults, children, pregnancy, breastfeeding, medical conditions, and people taking medications that affect metabolism.

Example 1: male coefficient, age 30, 70 kg, 175 cm, moderately active. Mifflin-St Jeor gives 1,648.75 kcal/day. Maintenance is 1,648.75 x 1.55 = 2,555.56, rounded to 2,556 kcal/day.

Example 2: a 10% deficit from that maintenance estimate is 2,555.56 x 0.90 = 2,300 kcal/day after rounding.

Example 3: female coefficient, age 35, 150 lb, 5 ft 5 in, lightly active. Inputs convert to about 68.04 kg and 165.1 cm. BMR is about 1,376 kcal/day and maintenance is about 1,892 kcal/day.

• Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition, 1990.
• Roza AM, Shizgal HM. The Harris Benedict equation reevaluated: resting energy requirements and the body cell mass. American Journal of Clinical Nutrition, 1984.
• National Academies of Sciences, Engineering, and Medicine. Dietary Reference Intakes for Energy, 2023.
• National Institute of Diabetes and Digestive and Kidney Diseases: Body Weight Planner and weight-management resources.
• Dietary Guidelines for Americans: federal dietary guidance context.
• CDC and federal maternal-health resources for pregnancy and breastfeeding calorie context.