How Many Calories Should You Eat?
Your daily calorie needs depend on age, sex, weight, height, and activity level. This calculator uses the Mifflin-St Jeor equation - the most accurate formula for estimating Basal Metabolic Rate - to give you a personalized daily calorie target for maintaining, losing, or gaining weight.
How Your Calorie Needs Are Calculated
We use the Mifflin-St Jeor equation, widely considered the most accurate formula for estimating Basal Metabolic Rate (BMR):
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age - 161
Then we multiply BMR by an activity factor (1.2 to 1.9) to get your Total Daily Energy Expenditure (TDEE).
Activity Level Multipliers
| Activity Level | Description | Multiplier |
|---|---|---|
| Sedentary | Little or no exercise | 1.2 |
| Lightly active | Exercise 1-3 days/week | 1.375 |
| Moderately active | Exercise 3-5 days/week | 1.55 |
| Very active | Exercise 6-7 days/week | 1.725 |
| Extra active | Hard exercise + physical job | 1.9 |
Worked Example: 35-Year-Old Woman
- Weight: 65 kg
- Height: 165 cm
- Age: 35
- Activity: moderately active (1.55)
- BMR = 10(65) + 6.25(165) - 5(35) - 161 = 1,340
- TDEE = 1,340 × 1.55 = 2,077 calories/day
- For weight loss: 2,077 - 500 = 1,577 calories/day
- For weight gain: 2,077 + 300 = 2,377 calories/day
Calorie Targets by Goal
| Goal | Daily Calories | Expected Weekly Change |
|---|---|---|
| Aggressive loss | TDEE - 1000 | -2 lb/week |
| Moderate loss | TDEE - 500 | -1 lb/week |
| Maintenance | TDEE | 0 |
| Moderate gain | TDEE + 300 | +0.5 lb/week |
| Aggressive gain | TDEE + 500 | +1 lb/week |
Frequently Asked Questions
How many calories should I eat to lose weight?
A safe deficit is 500 calories/day below your TDEE, producing about 1 lb loss per week. Deficits above 1000/day risk muscle loss and nutrient deficiency.
Is 1,200 calories a day enough?
For most adults, 1,200 calories is the minimum for safe weight loss - and only appropriate for smaller, sedentary women. Below 1,200 requires medical supervision.
Do calories from different foods matter?
Yes. 1,500 calories of whole foods (lean protein, vegetables, whole grains) produces very different results than 1,500 calories of processed foods, even though the energy is the same.
How accurate is the Mifflin-St Jeor equation?
It is accurate within +/- 5% for most adults - the best of any published BMR formula. Individual metabolic variation still exists.
Should I eat back exercise calories?
If you used the sedentary multiplier, yes. If you used an active multiplier that already accounts for exercise, no - that would double-count.
Do I need to track calories forever?
No. Many people track for 4-8 weeks to learn portion sizes, then rely on habits and intuition.