How many calories should I eat a day?

The right number of calories depends on your age, gender, height, weight, and activity level. Most adults need between 1,600 and 3,000 calories per day. Use the Daily Calorie Intake Calculator above to get a personalised target based on the Mifflin-St Jeor formula.

How do I calculate my daily calorie needs?

First calculate your BMR (Basal Metabolic Rate) — the calories your body burns at rest — then multiply by an activity factor to get your TDEE (Total Daily Energy Expenditure). The Mifflin-St Jeor formula is used here: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5 for men, or −161 for women.

How many calories should I eat to lose weight?

To lose weight safely, aim for a calorie deficit of 300–500 calories per day below your TDEE. This typically results in 0.3–0.5 kg (0.7–1 lb) of fat loss per week. Avoid deficits larger than 1,000 cal/day as these can lead to muscle loss and nutritional deficiencies.

BMR stands for Basal Metabolic Rate — the number of calories your body needs to sustain basic life functions (breathing, circulation, cell repair) at complete rest. It is the foundation of all calorie calculations. This calculator uses the Mifflin-St Jeor equation, which is considered the most accurate BMR formula for the general population.

TDEE stands for Total Daily Energy Expenditure. It is your BMR multiplied by an activity factor that accounts for how much you move each day. TDEE represents the total calories you burn in a day and is your true maintenance calorie level — eat at TDEE and your weight stays the same.

How many calories should a woman eat per day?

Most adult women need between 1,600 and 2,400 calories per day, depending on age, height, weight, and activity level. Sedentary women typically need around 1,600–1,800 cal/day, while very active women may need 2,200–2,400 cal/day or more. Use the calculator above for a personalised estimate.

How many calories should a man eat per day?

Most adult men need between 2,000 and 3,000 calories per day. A sedentary man typically needs around 2,000–2,200 cal/day, while very active men or athletes may need 2,800–3,200 cal/day. The exact figure depends on age, height, weight, and activity level.

How many calories should I eat to gain muscle?

To build muscle, you need a calorie surplus — eating more than your TDEE. A modest surplus of 200–300 calories per day (sometimes called a 'lean bulk') helps minimise fat gain while supporting muscle growth. This calculator recommends TDEE + 250 cal/day as a starting point for muscle gain.

Calorie Calculator

Calculate your daily calorie needs using the Mifflin-St Jeor equation — the most accurate BMR formula available. Works for both men and women. Enter your age, weight, height, and activity level to get your personalised calorie target for weight loss, maintenance, or muscle gain.

Why use our online Calorie Calculator?

Estimate your Total Daily Energy Expenditure (TDEE) and daily calorie needs based on your age, height, weight, and activity level. Use the result to set a deficit or surplus for your goal.

How to use Calorie Calculator

1
Enter your age, gender, height, and weight
Fill in your details at the top of the Daily Calorie Intake Calculator. Use the metric/imperial toggle to switch units — your values convert automatically.
2
Select your activity level
Click one of the five activity level cards that best describes your typical week. Choosing accurately is important — most people are Sedentary or Lightly Active.
3
Choose your goal
Select Lose Weight, Maintain, or Gain Muscle using the three buttons at the top of the calculator. This highlights your recommended daily calorie target.
4
Read your BMR and daily calorie targets
Your BMR (calories burned at rest) and TDEE (calories burned with activity) are shown, along with all three goal targets simultaneously so you can compare them.
5
Use the deficit, burned, macro, and food calculators
Scroll down to calculate your calorie deficit for a weight loss target, calories burned from exercise, your ideal macro split, or look up calories in common foods.

BMR formulas compared — Mifflin-St Jeor vs Harris-Benedict

Basal Metabolic Rate (BMR) formulas estimate the calories your body burns at complete rest. Several competing formulas have been developed over the past century, with varying accuracy.

The Harris-Benedict equation was the standard for most of the 20th century (men: BMR = 66.47 + 13.75W + 5.003H − 6.755A; women: BMR = 655.1 + 9.563W + 1.850H − 4.676A, where W=weight kg, H=height cm, A=age). Studies in the 1990s found it consistently overestimates BMR by 5% for overweight individuals.

The Mifflin-St Jeor equation (1990) was validated against measured resting metabolic rate in a broad population sample and is consistently more accurate: men: BMR = 10W + 6.25H − 5A + 5; women: BMR = 10W + 6.25H − 5A − 161. A 2005 meta-analysis in the Journal of the American Dietetic Association found Mifflin-St Jeor predicted measured RMR within 10% for 82% of individuals — significantly better than Harris-Benedict at 62%. This tool uses Mifflin-St Jeor.

The Katch-McArdle formula is potentially more accurate for lean, muscular individuals because it uses lean body mass rather than total weight, removing the dilution effect of body fat. However, it requires knowing your body fat percentage accurately.

Activity multipliers — why most people overestimate their level

The TDEE (Total Daily Energy Expenditure) is calculated by multiplying BMR by an activity factor. The standard activity levels and multipliers are: Sedentary (little or no exercise, desk job) × 1.2; Lightly Active (1–3 days/week of exercise) × 1.375; Moderately Active (3–5 days/week) × 1.55; Very Active (6–7 days/week of hard exercise) × 1.725; Extremely Active (physical labor job + twice daily training) × 1.9.

Research consistently shows that most people overestimate their activity level. Someone who goes to the gym three times a week but sits at a desk the remaining 16+ hours per day is likely Lightly Active, not Moderately Active. This overestimation causes TDEE to be overstated, which explains why eating "at maintenance" often results in weight gain.

The most accurate approach for individuals who genuinely want to know their TDEE: track food intake meticulously for 2–3 weeks while maintaining stable weight, then calculate the average daily intake. That average is your actual TDEE — a measured result rather than a formula estimate. Formula estimates have 10–20% individual variation even when activity is accurately reported.

Macros — how to split calories between protein, carbs, and fat

Once you know your daily calorie target, the next question is how to allocate those calories among the three macronutrients. Each gram of protein = 4 calories; each gram of carbohydrate = 4 calories; each gram of fat = 9 calories.

Protein is the most important macro for body composition. The current evidence-based recommendation for active individuals is 1.6–2.2 grams of protein per kilogram of body weight per day. For a 70 kg (154 lb) person, this is 112–154 grams of protein — about 450–615 calories from protein. Higher protein intakes support muscle retention during calorie deficits and muscle synthesis during surpluses. Protein is also the most satiating macro, making it the priority for fat loss phases.

Fat should not drop below 0.5–0.7 g/kg/day (roughly 20–25% of calories) to support hormonal function — particularly sex hormone production, which requires dietary fat. Very low fat intakes are associated with reduced testosterone in men and menstrual irregularities in women.

Carbohydrates fill the remaining calories and are the primary fuel for intense training. They are not essential (the body can produce glucose from protein and fat), but adequate carbohydrates support workout performance and recovery. The split: set protein first, set fat at a minimum floor, allocate remaining calories to carbohydrates.

Frequently Asked Questions

How many calories should I eat a day?: The right number of calories depends on your age, gender, height, weight, and activity level. Most adults need between 1,600 and 3,000 calories per day. Use the Daily Calorie Intake Calculator above to get a personalised target based on the Mifflin-St Jeor formula.
How do I calculate my daily calorie needs?: First calculate your BMR (Basal Metabolic Rate) — the calories your body burns at rest — then multiply by an activity factor to get your TDEE (Total Daily Energy Expenditure). The Mifflin-St Jeor formula is used here: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5 for men, or −161 for women.
How many calories should I eat to lose weight?: To lose weight safely, aim for a calorie deficit of 300–500 calories per day below your TDEE. This typically results in 0.3–0.5 kg (0.7–1 lb) of fat loss per week. Avoid deficits larger than 1,000 cal/day as these can lead to muscle loss and nutritional deficiencies.
What is BMR?: BMR stands for Basal Metabolic Rate — the number of calories your body needs to sustain basic life functions (breathing, circulation, cell repair) at complete rest. It is the foundation of all calorie calculations. This calculator uses the Mifflin-St Jeor equation, which is considered the most accurate BMR formula for the general population.
What is TDEE?: TDEE stands for Total Daily Energy Expenditure. It is your BMR multiplied by an activity factor that accounts for how much you move each day. TDEE represents the total calories you burn in a day and is your true maintenance calorie level — eat at TDEE and your weight stays the same.
How many calories should a woman eat per day?: Most adult women need between 1,600 and 2,400 calories per day, depending on age, height, weight, and activity level. Sedentary women typically need around 1,600–1,800 cal/day, while very active women may need 2,200–2,400 cal/day or more. Use the calculator above for a personalised estimate.
How many calories should a man eat per day?: Most adult men need between 2,000 and 3,000 calories per day. A sedentary man typically needs around 2,000–2,200 cal/day, while very active men or athletes may need 2,800–3,200 cal/day. The exact figure depends on age, height, weight, and activity level.
How many calories should I eat to gain muscle?: To build muscle, you need a calorie surplus — eating more than your TDEE. A modest surplus of 200–300 calories per day (sometimes called a 'lean bulk') helps minimise fat gain while supporting muscle growth. This calculator recommends TDEE + 250 cal/day as a starting point for muscle gain.

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