Calorie Calculator
How Many Calories Do You Actually Need?
Calorie targets are personal — they depend on your size, age, sex, and how active you are. This calculator uses one of the most validated formulas available to estimate your daily maintenance calories and give you specific targets for losing weight, gaining weight, or staying exactly where you are.
How to Use This Calculator
Enter your age, gender, weight, and height, then select the activity level that honestly describes your typical week. Hit Calculate Calories to see your maintenance number, your BMR (what you'd burn at complete rest), and specific daily calorie targets for losing 1 lb/week, losing 2 lbs/week, or gaining 1 lb/week.
How the Formula Works
This calculator uses the Mifflin-St Jeor equation to estimate your Basal Metabolic Rate (BMR) — the calories your body burns just to stay alive — then multiplies it by an activity factor to get your Total Daily Energy Expenditure (TDEE):
Female BMR = (10 × kg) + (6.25 × cm) − (5 × age) − 161
Your TDEE — the maintenance calorie number — is your BMR multiplied by your activity level (1.2 for sedentary up to 1.9 for extra active). Eat at TDEE and your weight stays stable. Eat below it and you lose weight. Eat above it and you gain.
Real-World Example
For a 30-year-old male, 175 lbs, 5'10", moderately active (the calculator's defaults):
- BMR: ~1,760 cal/day
- Maintenance (TDEE): ~2,728 cal/day
- Lose 1 lb/week: ~2,228 cal/day
- Lose 2 lbs/week: ~1,728 cal/day
- Gain 1 lb/week: ~3,228 cal/day
The "lose 2 lbs/week" target of 1,728 calories is workable but demanding — it requires a 1,000 calorie daily deficit, which leaves little room for error and can feel restrictive. Most people find the 1 lb/week target (500 cal deficit) more sustainable and just as effective over time.
Understanding the 3,500 Calorie Rule
The widely cited rule — 3,500 calories equals one pound of fat — is a useful approximation, not a precise equation. It comes from the energy density of fat tissue and forms the basis for the 500-calorie deficit = 1 lb/week calculation.
In practice, weight loss is rarely that linear. Early losses include water weight (which can make the first week look dramatic), and the body adapts over time by reducing energy expenditure as you lose mass — meaning a 500-calorie deficit produces slightly less than 1 lb/week the longer you maintain it. The rule is accurate enough for planning, but the scale will always be your real-world feedback.
Choosing the Right Calorie Target
The "best" calorie target is the one you can actually maintain:
- Lose 1 lb/week (−500 cal/day) — sustainable for most people, preserves muscle well, recommended for long-term fat loss
- Lose 2 lbs/week (−1,000 cal/day) — aggressive, suitable for short periods or those with significant weight to lose; increases risk of muscle loss without adequate protein and strength training
- Gain 1 lb/week (+500 cal/day) — a moderate bulk for muscle building; roughly half of this gain will be muscle, half fat in most cases
- Maintenance — eating at TDEE; useful during diet breaks, periods of high stress, or when you're satisfied with your current weight
Tips for Hitting Your Calorie Target
- Track for at least two weeks — most people significantly underestimate their food intake without tracking. Even a rough log for 2 weeks builds awareness that stays useful long after you stop counting.
- Prioritize protein — higher protein intake (0.7–1g per lb of bodyweight) keeps you fuller longer, preserves muscle during a deficit, and has a higher thermic effect than carbs or fat — meaning your body burns more calories digesting it.
- Build in flexibility — weekly averages matter more than daily perfection. Eating 200 calories over on Wednesday doesn't derail a week where you hit your target the other six days.
- Adjust every 4–6 weeks — as you lose weight, your maintenance calories decrease. Recalculate your target every month or two to keep your deficit accurate.
- Pair with the right tools — use our macro calculator to set protein, carb, and fat targets, and our TDEE calculator for a deeper breakdown of your energy expenditure.
Frequently Asked Questions
How many calories should I eat to lose weight?
Start with your maintenance calories from this calculator, then subtract 300–500 for a moderate deficit. This targets roughly 0.5–1 lb of weight loss per week. More aggressive deficits are possible but increase the risk of muscle loss, fatigue, and rebound eating. Slow and sustainable beats fast and unsustainable every time.
Is eating 1,200 calories a day safe?
For most adults, 1,200 calories is the lower boundary of what's considered safe for short-term weight loss — and even then only under medical supervision for some people. Below this level, it becomes very difficult to meet basic nutritional needs. If your calculated target falls below 1,200 (women) or 1,500 (men), consider a smaller deficit and a longer timeline rather than pushing further down.
Why am I not losing weight in a calorie deficit?
The most common reason is underestimating food intake — studies consistently show people underreport calories by 20–40%. Other factors include water retention masking fat loss on the scale, the body adapting by reducing NEAT (unconscious movement), and metabolic adaptation over longer deficit periods. If you've tracked carefully for 3+ weeks with no progress, try reducing calories by 100–150 and reassessing.
Do I need to count calories to lose weight?
No — but it helps most people, at least temporarily. Calorie counting builds nutritional awareness that tends to persist even after you stop. Alternatives like portion control, eating slowly, prioritizing whole foods, and reducing liquid calories can also work, but they're harder to calibrate precisely. If tracking causes stress or disordered thinking about food, it's not the right approach for you.
How accurate is calorie counting?
Less precise than most people assume. Food labels have a legal margin of error of up to 20%. Home cooking estimates can vary widely. Restaurant portions are notoriously inconsistent. And calorie expenditure estimates are just as approximate. That said, even imprecise tracking is far more useful than no tracking — a consistent 10–15% error in the same direction each day still produces predictable results if you adjust based on scale feedback.