Calorie Calculator
Find how many calories you need each day to lose, maintain, or gain weight, based on your body and activity level.
| Goal | Calories/day |
|---|---|
| Lose 1 lb/week | 2,190 |
| Lose 0.5 lb/week | 2,440 |
| Maintain weight | 2,690 |
| Gain 0.5 lb/week | 2,940 |
| Gain 1 lb/week | 3,190 |
Based on the Mifflin–St Jeor equation. A 500‑calorie daily deficit targets about 1 lb/week. Estimates only, not medical advice.
How to use this calculator
Enter your biological sex, age, height (feet and inches), and weight (pounds), then choose your typical activity level. The calculator returns your maintenance calories (TDEE) and daily targets for a mild deficit, a moderate deficit, and a modest surplus — so you can pick the goal that matches your situation.
How your daily calorie need is determined
Your total daily calorie burn has three main components:
- Basal Metabolic Rate (BMR): The calories your body needs to sustain organ function at complete rest. This is the largest component, accounting for roughly 60–70% of total expenditure.
- Thermic Effect of Food (TEF): The energy used to digest and absorb food — roughly 10% of calories consumed for a mixed diet. This is built into the activity multipliers used here.
- Physical Activity: Everything from formal exercise to walking, fidgeting, and other non-exercise movement. This is the most variable component and the one you have the most control over.
Adding all three gives your TDEE — the calorie level that maintains your current weight. Eat at TDEE and weight stays stable. Eat less and you lose; eat more and you gain. The relationship is not perfectly linear for everyone, but it holds reliably over weeks and months.
Worked example — step by step
A 28-year-old woman, 5 feet 5 inches (165 cm), 135 lb(61.2 kg), with a moderately active lifestyle:
- BMR (Mifflin–St Jeor): 10 × 61.2 + 6.25 × 165 − 5 × 28 − 161 = ≈ 1,400 calories
- TDEE (×1.55 for moderate activity): 1,400 × 1.55 = ≈ 2,170 calories to maintain
- Mild deficit (−250): ≈ 1,920 calories → targets ≈ 0.5 lb loss per week
- Moderate deficit (−500): ≈ 1,670 calories → targets ≈ 1 lb loss per week
If she wanted to gain lean mass slowly, eating at roughly 2,420 calories (TDEE + 250) would support a gradual surplus without excessive fat gain.
How to choose your activity level
The activity multiplier is where most people go wrong. Be honest rather than optimistic:
- Sedentary (×1.2): Mostly sitting throughout the day, little or no planned exercise.
- Lightly active (×1.375): Walking occasionally, 1–3 light workouts per week.
- Moderately active (×1.55): Regular exercise 3–5 days per week, some standing during the day.
- Very active (×1.725): Hard training 6–7 days per week, or a physically demanding job.
- Extra active (×1.9): Intense daily training plus a very active job — competitive athletes or manual laborers who also train hard.
How to interpret your result
Use the maintenance number as a starting point, not a guarantee. Individual metabolisms vary. Track your food and weight for two to three weeks: if your weight is moving as expected, the estimate is working well for you. If not, adjust by 100–200 calories and reassess. Recalculate any time your weight changes by 10 lb or more, as BMR shifts with body weight.
Want to break your calories into protein, carbs, and fat targets? Our macro calculator does that automatically.
Common mistakes to avoid
- Using BMR instead of TDEE as your calorie target. BMR does not include any activity. Eating at BMR puts most people in a dangerously large deficit.
- Overestimating activity. Research consistently shows people overestimate how much they exercise. When in doubt, go one level lower and adjust upward if needed.
- Not recalculating as weight changes. TDEE decreases as you lose weight. Failing to adjust leads to plateaus that feel inexplicable.
- Chasing an extremely large deficit. Cutting more than 1,000 calories below TDEE risks muscle loss, nutrient deficiency, and metabolic adaptation that makes it harder to lose fat long term.
Estimates for general informational purposes, not medical or dietary advice. Consult a registered dietitian or physician for personalized nutrition guidance.
How we calculate this
We estimate your resting metabolic rate with the Mifflin–St Jeor equation, multiply by an activity factor to get maintenance calories (TDEE), then adjust by 250–500 calories for weight goals (≈0.5–1 lb/week). Estimates only; not medical advice.
Sources
Frequently asked questions
How many calories do I need per day?
Your daily calorie need depends on your size, age, biological sex, and how active you are. The calculator estimates your Total Daily Energy Expenditure (TDEE) — maintenance calories — then shows adjusted targets for losing or gaining weight. For most adults, maintenance falls somewhere between 1,600 and 3,000 calories per day.
How are daily calorie needs calculated?
The calculator first estimates your Basal Metabolic Rate (BMR) using the Mifflin–St Jeor equation, then multiplies it by an activity factor (1.2 to 1.9) to get your maintenance calories. Weight-loss targets subtract 250–500 calories from maintenance, aiming for 0.5–1 pound of loss per week.
How large a calorie deficit should I aim for?
A 500-calorie daily deficit generally produces about 1 pound of fat loss per week, which most nutrition professionals consider a sustainable pace for preserving muscle. Larger deficits can accelerate weight loss short-term but are harder to sustain and may lead to muscle loss and metabolic adaptation.
Why do calorie needs change so much with activity level?
Physical activity is the most variable component of daily calorie burn. A very active person can burn 30–50% more calories per day than a sedentary person of the same size, age, and sex. Even non-exercise activity — walking, standing, fidgeting — adds up significantly across a day.
What happens if I eat below my BMR?
Consistently eating below your BMR (the calories needed just to keep organs functioning) can impair metabolism, hormone production, and immune function over time. Very-low-calorie diets should only be followed under medical supervision. Most people should not eat below 1,200 calories (women) or 1,500 calories (men) without professional guidance.
How do I adjust if my weight stops changing?
Calorie needs shift as your weight changes, and the body can adapt to reduced intake over weeks. If your weight plateaus after 2–3 weeks without the expected change, recalculate your TDEE at your new weight and adjust your target by 100–200 calories in the appropriate direction.
Should I eat more on days I exercise?
The activity factor built into TDEE already accounts for planned exercise on average. If your workouts vary significantly day to day, some people prefer to eat at their sedentary TDEE and add back specific exercise calories on training days — a method called 'eat back calories'. Either approach works; pick the one you can track consistently.