Calorie Calculator — Free Daily Calorie Needs Calculator
Find exactly how many calories you need per day. Based on the science-backed Mifflin-St Jeor equation, this calculator estimates your maintenance calories plus targets for weight loss or gain — with macro splits included.
BMR 1,649 × moderate activity (1.55)
A calorie calculator estimates your Total Daily Energy Expenditure (TDEE) — the number of calories your body burns in a day — so you know exactly how much to eat to lose, maintain, or gain weight. This one uses the Mifflin-St Jeor equation, the formula most dietitians and researchers consider the most accurate for the general population.
How Many Calories Do You Need Each Day? (USDA Guidelines)
Short answer: The USDA Dietary Guidelines estimate 1,600–2,400 kcal/day for adult women and 2,000–3,000 kcal/day for adult men, depending on age and activity. For your personal number, use the calculator above — it adjusts for your exact weight, height, age, and activity level.
| Age | Women (sedentary → active) | Men (sedentary → active) |
|---|---|---|
| 19–30 | 1,800–2,400 | 2,400–3,000 |
| 31–50 | 1,800–2,200 | 2,200–3,000 |
| 51+ | 1,600–2,200 | 2,000–2,800 |
Source: U.S. Department of Agriculture, Dietary Guidelines for Americans. Ranges run from sedentary to active lifestyles.
How the Calculation Works
First the calculator finds your Basal Metabolic Rate (BMR) — the calories you burn at complete rest — then multiplies it by an activity factor:
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
TDEE = BMR × activity multiplier
Worked example: a 30-year-old man, 70 kg, 175 cm: BMR = 700 + 1,093.75 − 150 + 5 = 1,649 kcal. With moderate activity (×1.55), TDEE = 2,556 kcal/day to maintain weight.
BMR vs TDEE: What’s the Difference?
BMR (Basal Metabolic Rate) is the energy your body burns at complete rest — keeping you breathing, warm, and alive. For most adults it accounts for roughly 60–70% of all calories burned. TDEE (Total Daily Energy Expenditure) is BMR plus everything else: walking, working, exercising, even digesting food.
That distinction is why the calculator asks for your activity level. Two people with the same BMR can have TDEEs hundreds of calories apart — and TDEE is the number your weight goals should be built on: eat below it to lose, at it to maintain, above it to gain.
Activity Multipliers Explained
| Level | Multiplier | Means |
|---|---|---|
| Sedentary | 1.2 | Desk job, little or no exercise |
| Light | 1.375 | Light exercise 1–3 days/week |
| Moderate | 1.55 | Moderate exercise 3–5 days/week |
| Active | 1.725 | Hard exercise 6–7 days/week |
| Very active | 1.9 | Very hard training or physical job |
Be honest here — most people overestimate their activity. When in doubt, pick one level lower; you can adjust after 2–3 weeks of tracking your weight trend.
How Many Calories to Lose Weight?
One kilogram of body fat stores roughly 7,700 kcal. A daily deficit of 500 kcal therefore leads to about 0.5 kg of fat loss per week — the pace most guidelines recommend as safe and sustainable. Larger deficits work faster but cost more muscle and are harder to sustain. For gaining lean mass, a modest surplus of 200–300 kcal paired with strength training minimizes fat gain.
Weight-Loss Plateau? How to Break Through It
Hitting a wall after a few good weeks is normal — as you get lighter, your TDEE drops, so the deficit that worked at first slowly disappears. Work through this checklist before cutting further:
- Re-calculate your TDEE at your new weight — targets go stale every 5–10 kg lost.
- Audit honestly for 2–3 weeks: unlogged snacks, drinks, cooking oils, and “just a bite” portions are the usual culprits.
- Check your activity setting — most people overestimate; drop one level and compare.
- Protect sleep and steps: under 7 hours of sleep and a sedentary day can erase a 200-kcal deficit through extra hunger and less movement.
- Adjust by 100–200 kcal, not 500 — small corrections are sustainable and preserve muscle.
What About Macros?
Calories decide whether your weight moves; macros decide what that weight is. This calculator sets protein at 2 g per kg of body weight (the evidence-backed range for active people is 1.6–2.2 g/kg), fat at 30% of calories for hormone health, and fills the rest with carbohydrates for energy. Hit your protein target daily — it is the single highest-leverage macro habit.
How Much Protein Do You Really Need?
Protein is the highest-leverage macro: it preserves muscle in a deficit, keeps you fuller, and costs more energy to digest. General targets by goal:
| Goal | Daily protein target | Example (70 kg person) |
|---|---|---|
| Basic RDA minimum | 0.8 g/kg | 56 g |
| Active lifestyle | 1.2–1.6 g/kg | 84–112 g |
| Losing fat / building muscle | 1.6–2.2 g/kg | 112–154 g |
| Adults 60+ | 1.0–1.2 g/kg | 70–84 g |
This calculator sets protein at 2 g/kg — the top of the evidence-backed range for active people — then assigns 30% of calories to fat for hormone health and fills the rest with carbohydrates.
What Is the Minimum Safe Calorie Intake?
As a general rule, adults should not drop below about 1,200 kcal/day (women) or 1,500 kcal/day (men) without medical supervision — below that it becomes very hard to get enough protein, vitamins, and minerals, and risks include muscle loss, gallstones, and hormonal disruption. Very-low-calorie diets exist, but they are medical programs with doctor monitoring, not DIY plans.
If your calculated “lose weight” target lands near these floors, choose a slower rate of loss instead of pushing lower. When in doubt, talk to your doctor or a registered dietitian before eating at a steep deficit.
Who Shouldn’t Use Standard Calorie Targets?
- Children and teens — growing bodies need enough energy; calorie targets for under-18s should come from a pediatrician, not a calculator.
- Pregnant or breastfeeding women — needs rise (roughly +340 kcal/day in the second trimester, +450 in the third), but targets should be personalized by your clinician.
- People with a history of eating disorders — calorie counting can be harmful; work with a professional instead.
- Competitive athletes — very high training loads need sport-specific fueling guidance.
Related calculators: Body Fat Calculator · BMI Calculator · Water Intake Calculator
Calorie FAQs
How many calories should I eat a day?
It depends on your size, age, sex, and activity. As a rough guide, moderately active adults need around 2,000–2,600 kcal (women) or 2,400–3,000 kcal (men) — but use the calculator above for your personal number.
What is the difference between BMR and TDEE?
BMR (Basal Metabolic Rate) is what you burn at total rest. TDEE (Total Daily Energy Expenditure) is BMR plus everything else — movement, exercise, digestion — and is the number that matters for weight goals.
Is the Mifflin-St Jeor equation accurate?
It is the most validated formula for the general population, typically within 10% of lab-measured values. Very muscular or obese individuals may need adjusted formulas or professional testing.
How fast can I safely lose weight?
About 0.5–1% of body weight per week (roughly 0.5 kg/week for most people) via a 300–500 kcal daily deficit. Faster loss usually sacrifices muscle.
Do I need to count macros or just calories?
Calories control weight change; protein controls how much of it is fat vs muscle. At minimum, hit your calorie target and eat ~2 g of protein per kg of body weight daily.
Why am I not losing weight on my calorie target?
The usual culprits: underestimating portions, unlogged snacks and drinks, or an activity level set too high. Track honestly for 2–3 weeks, then adjust by 100–200 kcal.
What is the minimum safe number of calories per day?
As a general guide, stay above roughly 1,200 kcal/day (women) or 1,500 kcal/day (men) unless a doctor is supervising you. Below that, nutrient deficiencies, muscle loss, and hormonal problems become likely.
How much protein should I eat each day?
At least 0.8 g/kg as a minimum; 1.6–2.2 g/kg if you are active, dieting, or building muscle (112–154 g for a 70 kg person). Older adults should aim for 1.0–1.2 g/kg.
Can teenagers use a calorie calculator?
No — teens are still growing and need enough energy for development. Calorie targets for under-18s should come from a pediatrician, not an online calculator.
How many calories do I need while pregnant or breastfeeding?
Needs rise — roughly 340 extra kcal/day in the second trimester and 450 in the third — but pregnancy targets should be personalized by your doctor or midwife.
Why does the USDA table differ from my calculator result?
The USDA ranges are population averages by age and sex. The calculator personalizes further using your exact weight, height, and activity level, so small differences are expected — trust the personalized number.
Should I eat back the calories I burn exercising?
Usually not fully — the activity multiplier in your TDEE already accounts for typical exercise. Eating back watch-estimated “burn” often double-counts and erases your deficit.
Last updated: October 2026. This calculator gives educational estimates based on the Mifflin-St Jeor equation — not medical advice. Calorie needs vary with health conditions and medications; consult your doctor or a registered dietitian before making big dietary changes, especially if you are pregnant, under 18, or managing a condition. Sources: USDA Dietary Guidelines for Americans; Mifflin et al., American Journal of Clinical Nutrition 1990; CDC.