Calorie deficit calculator

A calorie deficit means consuming less energy than your body uses. If you know your maintenance calories, enter that number. Otherwise, select the estimate option and enter adult body measurements and overall activity.

Deficit = maintenance × percentage ÷ 100
Estimated intake = maintenance − deficit

For example, a 20% deficit from 2,500 maintenance calories equals 500 kcal. The resulting intake is 2,000 kcal per day. Choosing a percentage is a way to compare arithmetic scenarios, not a recommendation that this deficit is right for you.

What this result cannot predict

Your energy expenditure changes with body size, activity and other factors. This calculator does not predict a weight-loss deadline or assume a fixed number of calories always equals a pound of weight loss. The NIDDK Body Weight Planner offers a different model for eligible adults who need to explore weight change over time.

Why some results are blocked

This tool accepts deficits from 5% to 25% and does not display targets below 1,200 kcal per day. That is a conservative product boundary, not proof that 1,200 kcal—or any higher result—is sufficient for you. Medical conditions, medications, eating-disorder concerns, pregnancy and breastfeeding call for individual guidance.

Mifflin–St Jeor resting energy

The calculator uses the commonly rounded form of the Mifflin–St Jeor equation. It estimates resting energy expenditure from body size, age and a sex coefficient. Resting energy is often labeled BMR in calculators, although laboratory BMR and resting-energy measurements differ.

Resting kcal/day = 10 × weight in kg + 6.25 × height in cm − 5 × age + coefficient
Male coefficient: +5. Female coefficient: −161.
Estimated TDEE = resting kcal/day × activity multiplier.

Choose activity for your whole day

The activity levels below are this tool’s rough planning assumptions. They are separate from the published resting-energy equation and do not measure your personal energy expenditure.

• 1.2: mostly seated, little intentional exercise.
• 1.375: some regular movement or light exercise.
• 1.55: regular exercise plus ordinary daily movement.
• 1.725: substantial daily movement and frequent training.
• 1.9: unusually demanding physical work or training.

A sedentary job with a few workouts can still produce a different total from a physically active job. If you are unsure, compare nearby levels rather than treating one result as exact.