Daily Calorie Needs Calculator
Estimates your daily maintenance calories (TDEE) with the revised Harris-Benedict equation and an activity multiplier. Use the result as the starting point for a weight-loss calorie deficit.
Last updated: September 2026
Formula below · 3 sources (dietaryguidelines.gov, CDC, Wikipedia) · Updated Sep 2026
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About this calculator
The calculator uses the revised Harris-Benedict equation (Roza and Shizgal, 1984) to estimate basal metabolic rate (BMR): for males, BMR = 88.362 + 13.397 × weight(kg) + 4.799 × height(cm) − 5.677 × age; for females, BMR = 447.593 + 9.247 × weight(kg) + 3.098 × height(cm) − 4.330 × age. It then multiplies BMR by the activity level (1.2 sedentary to 1.9 extremely active) to give Total Daily Energy Expenditure (TDEE), the calories you burn per day at your current weight. That maintenance figure is the result; it does not take a target weight or produce a timeline. To lose weight, eat below it: a deficit of about 500 kcal/day removes roughly 3,500 kcal (about 0.45 kg of fat) per week, and 7,700 kcal is a commonly used figure for 1 kg of body fat. Because TDEE falls as you lose weight, recalculate with your new weight every 5 kg or so. Harris-Benedict tends to run slightly higher than the Mifflin-St Jeor equation used by most of this site's other calorie calculators, typically by 50–100 kcal/day.
How to use
Example: 30-year-old male, 85 kg, 175 cm, lightly active (activity level 1.375). Step 1: BMR = 88.362 + 13.397 × 85 + 4.799 × 175 − 5.677 × 30 = 88.362 + 1,138.745 + 839.825 − 170.31 = 1,896.6 kcal/day. Step 2: TDEE = 1,896.6 × 1.375 ≈ 2,607.9 kcal/day, his maintenance intake. Step 3: for about 0.5 kg of fat loss per week he would eat roughly 2,608 − 550 ≈ 2,060 kcal/day (550 × 7 ≈ 3,850 kcal ≈ 0.5 kg). Recalculate after every 5 kg lost, because the maintenance figure drops with body weight.
Frequently asked questions
How many calories do I need to cut per day to lose 1 kg per week?
One kilogram of fat contains approximately 7,700 kilocalories, so to lose 1 kg per week you need a daily deficit of about 1,100 kcal (7,700 ÷ 7). For most people, this is an aggressive target that requires both dietary restriction and significant exercise. A more sustainable deficit of 500–600 kcal/day produces roughly 0.45–0.55 kg of fat loss per week. Very large deficits risk muscle loss, nutrient deficiencies, and metabolic slowdown, which is why most guidelines recommend losing no more than 0.5–1% of body weight per week.
Why does my calorie target need to decrease as I lose weight?
Your TDEE is directly tied to your body mass because larger bodies require more energy to maintain basic functions and to move. As you lose weight, your BMR drops because you have less metabolically active tissue. This means the same diet that produced a 500 kcal/day deficit early in your journey will produce a smaller deficit later—a phenomenon sometimes called 'metabolic adaptation.' Adjusting your intake progressively downward (or increasing exercise output) as you lose weight is essential to maintain your rate of progress. This calculator gives your maintenance calories at your current weight, so re-run it with your new weight every few kilograms to keep the deficit accurate.
What activity level multiplier should I use in the calorie deficit calculator?
Activity multipliers (also called PAL factors) are applied to BMR to estimate total daily expenditure. Sedentary (desk job, little exercise) uses 1.2; lightly active (light exercise 1–3 days/week) uses 1.375; moderately active (moderate exercise 3–5 days/week) uses 1.55; very active (hard exercise 6–7 days/week) uses 1.725; and extra active (physical job plus daily training) uses 1.9. Most adults with standard office jobs and casual gym sessions fall into the lightly to moderately active range (1.375–1.55). Overestimating your activity level is one of the most common reasons calculated deficits don't translate into expected weight loss.