Calorie Calculator – Daily Calorie Needs (TDEE)
By Talcart · Last updated July 10, 2026
Calorie Calculator Guide
Understanding Calorie Needs
BMR Formula (Mifflin-St Jeor)
Men: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age + 5
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age - 161
Activity Multipliers
Sedentary: BMR × 1.2
Lightly active: BMR × 1.375
Moderately active: BMR × 1.55
Very active: BMR × 1.725
Extremely active: BMR × 1.9
Weight Goals
Maintain weight: TDEE calories
Lose weight: Reduce by 500-1000 calories/day
Gain weight: Add 500-1000 calories/day
Calorie Calculator – Daily Calorie Needs (TDEE)
This calorie calculator estimates your Total Daily Energy Expenditure (TDEE) — for example, a moderately active 30-year-old woman of 165 cm and 65 kg burns roughly 2,124 kcal per day. Enter your age, sex, height, weight, and activity level to get your maintenance calories, plus adjusted targets for losing or gaining weight at a safe rate.
Key facts
- A deficit of about 500 kcal/day produces roughly 1 lb (0.45 kg) of weight loss per week, based on the approximation that 1 lb of body fat stores about 3,500 kcal.
- The CDC recommends a gradual weight-loss rate of 1-2 lb (0.45-0.9 kg) per week.
- Standard TDEE activity multipliers range from 1.2 (sedentary) to 1.9 (extremely active), applied to BMR.
- U.S. Dietary Guidelines estimate adult needs at roughly 1,600-2,400 kcal/day for women and 2,000-3,000 kcal/day for men, depending on age and activity.
What is the Calorie Calculator?
A calorie calculator estimates Total Daily Energy Expenditure (TDEE): the total kilocalories a person burns in 24 hours through basal metabolism, digestion, daily movement, and exercise. Basal metabolism alone typically accounts for 60-75% of the total, with physical activity and the thermic effect of food making up the rest. Knowing your TDEE lets you set an evidence-based intake: eat near it to maintain weight, below it to lose, or above it to gain. Results are estimates — individual metabolism varies, so adjust based on real-world results and consult a healthcare provider before major dietary changes.
How does the Calorie Calculator work?
The calculator first computes Basal Metabolic Rate with the Mifflin-St Jeor equation: BMR = 10 x weight (kg) + 6.25 x height (cm) - 5 x age + 5 for men, or - 161 for women. It then multiplies BMR by a standard activity factor from 1.2 (sedentary) through 1.375 (light), 1.55 (moderate), and 1.725 (very active) up to 1.9 (extremely active) to produce TDEE. Goal targets are derived from TDEE — commonly a 500 kcal/day deficit for weight loss of about 1 lb (0.45 kg) per week, or a modest surplus for gaining.
What is the Calorie Calculator formula?
- w – weight in kg
- h – height in cm
- a – age in years
- Activity factor – 1.2 (sedentary) to 1.9 (very active)
Estimated daily calorie needs by age, sex, and activity (U.S. Dietary Guidelines)
| Group | Sedentary | Moderately active | Active |
|---|---|---|---|
| Women 19-30 | 1,800 - 2,000 kcal | 2,000 - 2,200 kcal | 2,400 kcal |
| Women 31-50 | 1,800 kcal | 2,000 kcal | 2,200 kcal |
| Women 51+ | 1,600 kcal | 1,800 kcal | 2,000 - 2,200 kcal |
| Men 19-30 | 2,400 - 2,600 kcal | 2,600 - 2,800 kcal | 3,000 kcal |
| Men 31-50 | 2,200 - 2,400 kcal | 2,400 - 2,600 kcal | 2,800 - 3,000 kcal |
| Men 51+ | 2,000 - 2,200 kcal | 2,200 - 2,400 kcal | 2,400 - 2,800 kcal |
How do you use the Calorie Calculator?
- Select your sex.
- Enter your age, height, and weight.
- Pick the activity level that best matches your week.
- Read your maintenance, cutting, and bulking targets.
Worked example
| Scenario | 30-year-old woman, 165 cm, 65 kg, moderately active |
| Calculation | BMR = 10(65) + 6.25(165) − 5(30) − 161 = 1370.25; TDEE = 1370.25 × 1.55 ≈ 2124 |
| Result | About 2,124 kcal/day to maintain weight. |
Common use cases
Tips & best practices
For weight loss, aim for a 300–500 kcal/day deficit — fast losses are usually water and muscle.
Reassess every 4–6 weeks as your weight changes.
Frequently asked questions
Most adult women need roughly 1,600-2,400 kcal per day and most adult men need 2,000-3,000 kcal, according to the U.S. Dietary Guidelines — the exact figure depends on age, size, and activity level. A calorie calculator narrows this down by computing your BMR with the Mifflin-St Jeor equation and multiplying by your activity factor, giving a personalized maintenance estimate rather than a broad population range.
Eat about 500 kcal per day below your maintenance calories to lose roughly 1 lb (0.45 kg) per week — the gradual rate the CDC associates with lasting results. The CDC recommends losing no more than 1-2 lb per week. Avoid dropping below about 1,200 kcal/day (women) or 1,500 kcal/day (men) without medical supervision, and consult a healthcare provider before starting any significant deficit.
TDEE (Total Daily Energy Expenditure) is every calorie you burn in a day: basal metabolism, digestion, everyday movement, and exercise. It is calculated as BMR x activity factor. Using Mifflin-St Jeor, a 40-year-old man of 180 cm and 80 kg has a BMR of 1,730 kcal; if moderately active (factor 1.55), his TDEE is about 2,682 kcal per day.
A modest surplus of about 250-500 kcal per day above TDEE, combined with resistance training and adequate protein, supports muscle gain while limiting fat gain. Larger surpluses mostly add body fat rather than extra muscle. Track your weight over several weeks: gaining faster than about 0.25-0.5% of body weight per week usually means the surplus is bigger than needed.
The most common reason is that intake is higher or expenditure lower than estimated — calculator outputs are estimates, and studies consistently find people under-report what they eat. Metabolic rate also adapts modestly as weight drops, shrinking the deficit over time. Recheck portion tracking, recalculate your TDEE at your new weight, and if weight still will not move, discuss it with a healthcare provider.
For many adults, 1,200 kcal per day is the lowest intake generally considered safe for women without medical supervision (about 1,500 kcal for men), because meeting vitamin, mineral, and protein needs below that is difficult. Very-low-calorie diets under 800 kcal are used only under medical care. A moderate 500 kcal deficit from your calculated TDEE is safer and easier to sustain.
Yes — energy needs decline gradually through adulthood as basal metabolic rate falls and activity typically decreases. In the Mifflin-St Jeor equation, each additional year of age subtracts 5 kcal from daily BMR, roughly 50 kcal per decade. U.S. Dietary Guidelines ranges reflect this: a sedentary woman needs about 1,800 kcal at 25 but about 1,600 kcal at 60.