Estimate daily maintenance calories (TDEE) from your stats and activity level using the Mifflin-St Jeor equation.
Usage Tip
Track intake and weight for two weeks, then adjust against this estimate for accuracy.
What is BMR?
Your basal metabolic rate (BMR) is the energy your body uses at complete rest just to keep you alive – breathing, circulation, cell repair and brain function. It is the single biggest part of your daily calorie burn, typically 60–70% of the total, before any movement is added.
How TDEE is calculated
Total daily energy expenditure (TDEE) is your BMR multiplied by an activity factor that accounts for movement and exercise. This calculator uses the Mifflin-St Jeor equation for BMR, then applies your activity level:
BMR (men) = 10×kg + 6.25×cm − 5×age + 5
BMR (women) = 10×kg + 6.25×cm − 5×age − 161
TDEE = BMR × activity factor
Activity levels
| Level | Factor | Typical lifestyle |
|---|---|---|
| Sedentary | ×1.2 | Desk job, little or no exercise |
| Lightly active | ×1.375 | Light exercise 1–3 days a week |
| Moderately active | ×1.55 | Moderate exercise 3–5 days a week |
| Very active | ×1.725 | Hard exercise 6–7 days a week |
| Extra active | ×1.9 | Athlete, or physical job plus training |
Most people overestimate their activity level. If you are unsure, pick the lower option – it is the most common source of error in calorie estimates.
Calories needed to lose weight
To lose weight you eat fewer calories than you burn – a calorie deficit. Roughly 7,700 kcal equals 1 kg of body fat (about 3,500 kcal per pound), so a steady daily deficit translates into a predictable weekly change.
| Approach | Daily deficit | Weekly loss |
|---|---|---|
| Mild | −250 kcal | about 0.25 kg (0.5 lb) |
| Moderate | −500 kcal | about 0.5 kg (1 lb) |
| Aggressive | −1,000 kcal | about 1 kg (2 lb) |
Calories needed to gain weight
To build muscle or gain weight you eat slightly more than you burn – a calorie surplus, paired with resistance training and enough protein.
| Approach | Daily surplus | Weekly gain |
|---|---|---|
| Lean gain | +250 kcal | about 0.25 kg (0.5 lb) |
| Bulk | +500 kcal | about 0.5 kg (1 lb) |
A smaller surplus keeps more of the gain as muscle rather than fat. Muscle is built slowly – even for beginners, roughly 0.25–0.5 kg of actual muscle per month is realistic.
Calorie deficit and surplus, explained
A deficit means eating below your TDEE so the body draws on stored energy – that is how fat loss happens. A surplus means eating above your TDEE to provide extra material for growth. Maintenance is eating at your TDEE to hold steady. The size of the gap sets how fast your weight changes.
Printable calorie goal chart
Example goals for a TDEE of 2,500 kcal (subtract or add the same amounts to your own number):
| Goal | Calories/day |
|---|---|
| Aggressive loss (−1,000) | 1,500 |
| Moderate loss (−500) | 2,000 |
| Mild loss (−250) | 2,250 |
| Maintenance | 2,500 |
| Lean gain (+250) | 2,750 |
| Bulk (+500) | 3,000 |
Protein recommendations
Protein protects muscle in a deficit and builds it in a surplus. A common range for active people is about 1.6–2.2 g of protein per kg of body weight per day; a sedentary baseline is around 0.8 g/kg. For an 80 kg person aiming to build or keep muscle, that is roughly 130–175 g a day. The Macro Calculator turns your calorie goal into protein, carb and fat targets.
Healthy weight-loss guidance
A sustainable pace is about 0.5–1% of body weight per week. Pair a modest deficit with enough protein, strength training to preserve muscle, and plenty of fibre and water to stay full. Crash diets usually backfire: rapid loss is hard to keep off and often returns.
Realistic timelines
Weight loss: at a 500 kcal daily deficit, expect about 0.5 kg (1 lb) a week, or roughly 2 kg (4–5 lb) a month. Muscle gain: even with good training and nutrition, natural muscle gain is slow – about 0.25–0.5 kg of muscle per month, faster for beginners and slower with experience.
Common dieting mistakes
- Setting the deficit too aggressively, then burning out and rebounding.
- Not eating enough protein, so weight lost includes muscle.
- Overestimating activity level, which inflates the calorie target.
- Tracking inconsistently or forgetting drinks, oils and snacks.
- Expecting linear progress – weight fluctuates day to day with water and food in transit.
- Giving up after a week or two instead of judging the trend over a month.
Frequently asked questions
Why TDEE is an estimate
The Mifflin-St Jeor equation is based on population averages. Your actual needs depend on muscle mass, genetics, hormones, sleep and how much you move outside of exercise. Treat the result as a well-founded starting point: track your intake and weight for two to three weeks, then nudge the number up or down based on what actually happens.