Why does a deficit of 500 calories matter?

A pound of body fat stores roughly 3,500 calories, so a 500-calorie daily deficit corresponds to about one pound of loss per week. The same logic in reverse drives the 500-calorie surplus used for the gain goal.

How do I pick the right activity level?

Match it to your weekly movement: sedentary for desk-bound days, light for one to three workouts a week, moderate for three to five, active for six to seven, and very active for hard training or a physical job. Overestimating activity inflates the target.

Is this calorie target a guarantee of weight change?

No. It is an estimate. Real results depend on adherence, food accuracy, sleep, stress, and individual metabolism, so track your weight over a few weeks and adjust the target if progress stalls.

What is the difference between this and a BMR calculator?

A BMR calculator stops at resting calories. This tool goes further by adding your activity multiplier and a goal-based deficit or surplus to produce an actionable daily eating target.

Calorie Calculator

Gender

Age30 years

Height

Weight

lbs

Activity Level

Goal

Daily Calories2,763 cal

BMR1,783 cal/day

TDEE2,763 cal/day

This calculator estimates how many calories you should eat each day to lose, maintain, or gain weight. It first finds your resting metabolism (BMR) with the Mifflin-St Jeor equation, scales it by your activity level to get total daily energy expenditure (TDEE), then adjusts by a 500-calorie deficit or surplus for your goal. The result is a practical daily target you can build meals around.

Formula

Daily calories = (BMR × activity factor) ± 500

BMR: Basal metabolic rate from Mifflin-St Jeor (cal/day)
activity factor: 1.2 to 1.9 depending on activity level
±500: −500 to lose, 0 to maintain, +500 to gain (~1 lb per week)

How it works

Enter your sex, age, height in inches, and weight in pounds (converted internally to cm and kg), then pick an activity level and a goal of losing, maintaining, or gaining weight.
BMR is calculated with Mifflin-St Jeor and multiplied by an activity factor — 1.2 sedentary, 1.375 light, 1.55 moderate, 1.725 active, 1.9 very active — to give your TDEE.
For weight loss the tool subtracts 500 calories from TDEE; for gain it adds 500; maintenance keeps TDEE as-is. It displays your daily calorie target alongside your BMR and TDEE.

Worked example

A 30-year-old man, 70 in, 180 lb, moderately active, aiming to lose weight.

BMR (Mifflin-St Jeor) ≈ 1,783 cal/day.
TDEE = 1,783 × 1.55 ≈ 2,763 cal/day.
Weight-loss target = 2,763 − 500 = 2,263.

Daily target ≈ 2,263 cal (BMR 1,783, TDEE 2,763).

Frequently asked questions

Why does a deficit of 500 calories matter?: A pound of body fat stores roughly 3,500 calories, so a 500-calorie daily deficit corresponds to about one pound of loss per week. The same logic in reverse drives the 500-calorie surplus used for the gain goal.
How do I pick the right activity level?: Match it to your weekly movement: sedentary for desk-bound days, light for one to three workouts a week, moderate for three to five, active for six to seven, and very active for hard training or a physical job. Overestimating activity inflates the target.
Is this calorie target a guarantee of weight change?: No. It is an estimate. Real results depend on adherence, food accuracy, sleep, stress, and individual metabolism, so track your weight over a few weeks and adjust the target if progress stalls.
What is the difference between this and a BMR calculator?: A BMR calculator stops at resting calories. This tool goes further by adding your activity multiplier and a goal-based deficit or surplus to produce an actionable daily eating target.

Related calculators

BMR Calculator TDEE Calculator Macro Calculator Carbohydrate Calculator