Calorie Calculator

Calorie Calculator

Calculate your daily calorie needs for weight loss, maintenance, weight gain or muscle building.

  • Evidence-based formula
  • Free
  • No sign up
Enter your details
Sex
Height
ft
in
lb
Goal

Your data stays private and is not stored.

Your results will appear here

Once you enter your details, we'll show your maintenance calories, calorie targets, estimated macros, BMR, and TDEE.

Maintenance Calories

kcal / day
Lose weightkcal / day
Maintainkcal / day
Gain weightkcal / day

Estimated macros

Protein
%
Carbs
%
Fat
%

Based on your body weight, calorie target and goal.

BMR

kcal / day

TDEE

kcal / day

BMI

kg / m²

Daily calorie target

Get clear targets for lose, maintain, gain, or build muscle.

Estimated macros

See a practical starting protein, carb & fat split.

BMR & TDEE

Understand your base metabolism and daily burn.

How many calories do I need per day?

Your daily calorie needs depend on factors such as your age, sex, height, weight and activity level. This calorie calculator uses those details to estimate how much energy your body uses each day.

Your maintenance calories are your estimated daily energy needs for keeping your current body weight relatively stable. Eating below maintenance creates a calorie deficit, while eating above maintenance creates a calorie surplus.

There is no single calorie target that works for everyone. Metabolism, activity and other individual factors can affect your actual energy needs, so use your calculated result as a practical starting estimate rather than an exact requirement.

  • Maintenance≈ estimated daily energy use
  • Deficit ↓below maintenance
  • Surplus ↑above maintenance

How this calorie calculator works

  1. 1

    Enter your details

    Add your age, sex, height, weight and usual activity level.

  2. 2

    Estimate your calorie needs

    We estimate your BMR and adjust it for your activity level to estimate your total daily energy expenditure.

  3. 3

    Choose your goal

    Compare estimated calorie targets for weight loss, maintenance, weight gain and muscle building, plus estimated macros.

Calorie targets for weight loss, maintenance, weight gain & muscle building

Lose weight

A calorie target below your estimated maintenance calories. The calculator uses a moderate deficit as a practical starting point for weight loss.

Maintain

Calories around your estimated daily energy expenditure, intended to keep your body weight relatively stable.

Gain weight

A larger calorie surplus for increasing overall body weight. Weight gained can include muscle, body fat, glycogen and water.

Build muscle

A smaller, controlled calorie surplus intended to support muscle growth while limiting unnecessary fat gain. Resistance training is also necessary for building muscle.

All calorie targets are estimates and may need to be adjusted based on real-world progress.

Why can Build muscle require fewer calories than Gain weight?

Gain weight focuses on increasing overall body weight, so it uses a larger calorie surplus.

Build muscle uses a smaller, controlled surplus because eating more calories does not automatically create more muscle. Resistance training provides the stimulus for muscle growth, while an unnecessarily large surplus may also increase fat gain.

BMR vs TDEE: what's the difference?

BMR

Basal Metabolic Rate

BMR estimates how much energy your body uses at rest to support essential functions such as breathing, circulation and other basic body functions.

TDEE

Total Daily Energy Expenditure

TDEE estimates your total daily energy use after your BMR is adjusted for your usual activity level.

Simply put: BMR is your baseline energy estimate. TDEE is the estimate used as the starting point for your daily calorie target.

BMI 

Body Mass Index

BMI compares your weight to your height and is shown alongside your results as general context, not as a calorie number. It is calculated as weight in kilograms divided by height in metres squared:  underweight is below 18.5,  healthy weight 18.5–24.9,  overweight 25–29.9 obesity 30 or above.  BMI does not account for muscle mass or body composition, so athletes and very muscular people can fall into a higher category without excess body fat. Your calorie targets come from BMR and TDEE, not from BMI.

How we calculate your daily calorie needs

This calorie calculator uses the Mifflin–St Jeor equation to estimate Basal Metabolic Rate (BMR) from your age, sex, height and weight. Your BMR is then adjusted using your selected activity level to estimate Total Daily Energy Expenditure (TDEE).

Mifflin–St Jeor equation

For men

BMR = (10 × weight in kg)
+ (6.25 × height in cm)
− (5 × age)
+ 5

For women

BMR = (10 × weight in kg)
+ (6.25 × height in cm)
− (5 × age)
− 161

TDEE = BMR × activity factor

View activity factors
  • SedentaryLittle or no exercise1.2
  • Lightly activeExercise about 1–3 days/week1.375
  • Moderately activeExercise about 3–5 days/week1.55
  • Very activeExercise about 6–7 days/week1.725
  • Extra activeVery hard training or a physically demanding job1.9

BMR and TDEE are predictive estimates rather than direct measurements of your metabolism or daily energy expenditure.

How are my macros calculated?

Your estimated macros are based on your body weight, selected calorie target and goal.

Protein starts from a body-weight-based estimate and changes with your selected goal. Fat is estimated at approximately 30% of your calorie target, while carbohydrates make up the remaining calories.

These values are practical starting estimates rather than exact dietary requirements.

  • ProteinBody weight + goal
  • Fat≈ 30% of calories
  • CarbsRemaining calories
See how protein changes by goal

This calculator uses these simplified starting estimates:

  • Lose weight1.6 g/kg
  • Maintain1.4 g/kg
  • Gain weight1.4 g/kg
  • Build muscle1.6 g/kg

These values explain how this calculator generates its macro estimates. They are not individualized protein requirements.

Example calorie calculation

27-year-old woman · 180 cm · 62 kg · moderately active

  1. Step 1

    Estimate BMR

    Using the Mifflin–St Jeor equation for women:

    BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161

    Substitute the example values:

    BMR = (10 × 62) + (6.25 × 180) − (5 × 27) − 161

    BMR = 620 + 1,125 − 135 − 161

    BMR = 1,449 kcal/day

  2. Step 2

    Adjust for activity

    Moderately active uses an activity factor of 1.55.

    TDEE = BMR × activity factor

    TDEE = 1,449 × 1.55

    TDEE = 2,245.95

    ≈ 2,246 kcal/day

    This is the estimated maintenance calorie level.

  3. Step 3

    Calculate calorie targets

    • Lose weight15% deficit2,246 × 0.85≈ 1,909 kcal/day
    • MaintainMaintenance level2,246 × 1.00≈ 2,246 kcal/day
    • Gain weight15% surplus2,246 × 1.15≈ 2,583 kcal/day
    • Build muscle10% controlled surplus2,246 × 1.10≈ 2,471 kcal/day

These values are estimates. Actual energy needs and progress can vary between individuals.

How accurate is a calorie calculator?

A calorie calculator estimates energy needs; it does not directly measure your metabolism.

Predictive equations provide a useful starting point, but actual calorie needs vary between individuals. Activity, metabolism, health conditions and other factors can all affect daily energy expenditure.

Use your calculated target as a starting estimate and adjust it based on real-world changes over time.

This calculator is designed for adults aged 18 and over. It is not intended for pregnancy or breastfeeding. People with medical conditions, specialized athletic requirements or other circumstances that affect energy needs may require individualized guidance.

18+ · Individual estimates · Not for pregnancy or breastfeeding

Frequently asked questions

What is a calorie calculator?

A calorie calculator estimates how many calories your body may need each day based on factors such as age, sex, height, weight and activity level. It can then use your estimated maintenance calories to show targets for weight loss, maintenance, weight gain or muscle building.

How many calories should I eat per day?

Your calorie needs depend on age, sex, height, weight and activity. Estimated TDEE provides a useful starting point: eat around maintenance to keep weight relatively stable, below it for a deficit or above it for a surplus.

How do I calculate my maintenance calories?

Maintenance calories can be estimated by calculating BMR and adjusting it for activity. The resulting TDEE estimates how much energy you use during a typical day.

How many calories should I eat to lose weight?

A weight-loss calorie target is below estimated maintenance. This calculator uses a percentage-based deficit so the target scales with estimated energy expenditure instead of subtracting the same number of calories for everyone.

What is a calorie deficit?

A calorie deficit occurs when you consume less energy than your body uses. Sustaining an energy deficit over time can lead to weight loss, although individual results vary.

How many calories should I eat to gain weight?

Weight gain generally requires a calorie surplus above estimated maintenance. This calculator scales that surplus from estimated TDEE rather than using one fixed calorie target for everyone.

What's the difference between gaining weight and building muscle?

Gain weight uses a larger surplus aimed at increasing overall body weight. Build muscle uses a smaller controlled surplus, a higher protein estimate and assumes regular resistance training.

What's the difference between BMR and TDEE?

BMR estimates energy use at rest. TDEE adjusts that estimate for activity and represents estimated total daily energy expenditure.

Is this calorie calculator exact?

No. The calculator uses predictive equations and an estimated activity level. Its results are useful starting estimates rather than direct measurements of your calorie requirements.

Methodology & sources

We believe calorie calculator results should be transparent about where the numbers come from. This tool uses established predictive equations alongside clearly defined calculator assumptions, and all results are presented as estimates.

  • Mifflin–St Jeor equation for estimated BMR
  • Activity-adjusted TDEE
  • Percentage-based calorie targets
  • Body-weight-based protein estimates
  • Clearly labelled estimates and limitations

Sources