Calorie CalculatorHow Many Calories Should I Eat a Day?
Find your daily calorie needs to lose, maintain or gain weight. The calculator uses the Mifflin-St Jeor equation, shows every goal on one calorie ladder, and stops you going below a safe minimum.
Built & medically reviewed by Manzoor Ahmad, Pharmacist & Calculator Developer · Updated
Based on the Mifflin-St Jeor equation and the Dietary Guidelines for Americans estimated calorie needs.
How many calories should you eat a day?
Most adult women need about 1,600–2,400 calories a day and most men 2,000–3,000. To find your own number, work out your BMR with the Mifflin-St Jeor equation and multiply it by your activity level (1.2–1.9). That gives your maintenance calories. Subtract 500 a day to lose about 1 lb a week, or add 250–500 to gain.
Your details
feet · inches
−500 kcal/day ≈ 1 lb (0.45 kg) lost per week
Your maintenance is 2,125 kcal. Your body at rest burns 1,370 kcal.
Calorie ladder: every goal at a glance
Tap a rung to set it as your goal. Each rung is a daily target and the weekly change it produces.
Where your daily calories go
How many calories do you need a day? (USDA table)
Estimated daily calorie needs from the Dietary Guidelines for Americans, by age, sex and activity. Use the calculator for a figure based on your own height and weight.
| Age | Women · sedentary | Women · active | Men · sedentary | Men · active |
|---|---|---|---|---|
| 19–30 | 1,800–2,000 | 2,400 | 2,400–2,600 | 3,000 |
| 31–50 | 1,800 | 2,200 | 2,200–2,400 | 2,800–3,000 |
| 51–60 | 1,600 | 2,200 | 2,200 | 2,600–2,800 |
| 61+ | 1,600 | 2,000 | 2,000 | 2,400–2,600 |
How the calorie calculator works
We use the Mifflin-St Jeor equation, which the Academy of Nutrition and Dietetics found the most accurate predictive formula for healthy adults. It is usually within 10% of measured resting metabolism.
The “where your calories go” bar puts the thermic effect of food at 10% of intake, the standard estimate for a mixed diet.
Woman, 30, 5’5″ (165 cm), 143 lb (65 kg), moderately active
- BMR = 650 + 1,031 − 150 − 161 = 1,370 kcal
- Maintenance = 1,370 × 1.55 = 2,125 kcal
- Lose 1 lb/week: 2,125 − 500 = 1,625 kcal/day
- Lose 2 lb/week: 2,125 − 1,000 = 1,125, which is below the 1,200 floor, so the calculator caps it at 1,200
- Lean gain: 2,125 + 300 = 2,425 kcal/day
Why the “3,500 calories = 1 lb” rule slows down
The 500-a-day rule is a good starting point for the first 4–8 weeks. Over time, research from the NIH’s body-weight planner shows that loss slows. A smaller body burns fewer calories, and your body adapts by moving a little less without you noticing.
- Recalculate every 10 lb (4–5 kg) you lose.
- Judge progress by your 2-week average weight, not single weigh-ins, because water can swing 2–4 lb a day.
- A plateau of more than 3 weeks usually means you need about 100–200 kcal less, or more daily steps.
Medicines that change your calorie maths
Some prescriptions shift your appetite or your weight independently of calories. The common ones I see at the counter are oral steroids such as prednisone, insulin and sulfonylureas, some antidepressants (mirtazapine, paroxetine), antipsychotics such as olanzapine, and older antihistamines. If you’ve gained weight since starting one of these, don’t stop it. Talk to your prescriber about the alternatives.
On a GLP-1 medicine such as semaglutide or tirzepatide, the opposite problem is common: eating too little. If you’re far below the target above, focus on protein (aim for 1.2 g/kg or more) so the weight you lose isn’t muscle.
Related calculators
Calorie calculator FAQs
Most women need about 1,600–2,400 calories a day and most men 2,000–3,000, depending on age, height, weight and activity. For a personal number, the calculator estimates your BMR with the Mifflin-St Jeor equation, multiplies it by your activity level, and adjusts for your goal.
Eat about 500 calories below your maintenance level to lose roughly 1 lb (0.45 kg) a week. For a 30-year-old moderately active woman who weighs 143 lb, that’s about 1,625 calories a day. Avoid going below 1,200 calories (women) or 1,500 (men) without medical supervision.
For most healthy adults, the Mifflin-St Jeor equation is the most accurate predictive formula. It usually comes within 10% of measured resting metabolism. If you know your body fat percentage, the Katch-McArdle formula can be more accurate for very lean or very muscular people.
1,200 calories a day is the commonly used minimum for women without medical supervision, and 1,500 for men. Below that, it becomes hard to get enough protein, vitamins and minerals. Many active people lose weight comfortably on much more.
That’s your basal metabolic rate (BMR). For most adults it’s 1,200–1,800 calories a day for women and 1,500–2,100 for men. It accounts for about 60–70% of the calories you burn each day.
If you chose your activity level honestly, exercise is already counted in your maintenance calories, so don’t add it again. If you chose sedentary and log workouts separately, eat back about half of the exercise calories, because trackers tend to overestimate the burn.
The most common reasons are underestimating portions (by 20–40% in studies), water retention masking fat loss, and a slower metabolism as you get lighter. Track carefully for 2 weeks, use the average of your weigh-ins, then lower your intake by 100–200 calories if the trend is flat.
Eat about 250–500 calories above maintenance with 1.6–2.2 g of protein per kg of body weight, and lift weights. Aim to gain roughly 0.25–0.5% of your body weight a week, so most of the gain is muscle rather than fat.
Yes. Calorie needs fall slowly with age, mostly because of muscle loss and lower activity. The Mifflin-St Jeor equation subtracts 5 calories a day for every year of age, so a 50-year-old needs about 100 calories less than they did at 30, with all else equal.
Manzoor Ahmad
Pharmacist · Supplement & Nutrition Writer (9+ yrs) · Calculator Developer (13+ yrs)
I’m a practising pharmacist and I build DexoCalc’s calculators myself. This calorie calculator uses the formula dietitians trust most, and adds two things most calculators skip: a hard floor so it never recommends crash-diet numbers, and a note on the medicines that quietly change your calorie needs.
References
- Mifflin MD, St Jeor ST, et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241–247. PubMed
- Frankenfield D, et al. Comparison of predictive equations for resting metabolic rate. J Am Diet Assoc. 2005;105(5):775–789. PubMed
- USDA & HHS. Dietary Guidelines for Americans, 2020–2025, Appendix 2: Estimated Calorie Needs.
- Hall KD, et al. Quantification of the effect of energy imbalance on bodyweight. Lancet. 2011;378(9793):826–837. PubMed
- NIDDK. Body Weight Planner.
Medical disclaimer: Calorie estimates are for healthy adults and are not medical advice. If you are pregnant, breastfeeding, under 18, have diabetes or kidney disease, have a history of disordered eating, or take medicines that affect weight, speak to your doctor or a registered dietitian before changing how much you eat.