calorie calculator2026-09-17T20:40:56+01:00

FREE CALORIE CALCULATOR

Calorie Calculator: Calculate your daily calorie needs.

For fat loss, maintenance or muscle gain.

Calculate your daily calorie needs based on your body stats, activity level and goals.

ACCURATE

SCIENCE-BACKED CALCULATIONS

PERSONALISED

FOR YOUR BODY & GOALS

ACTIONABLE

RESULTS YOU CAN USE TODAY

1

Your Details

years
Sex
The Mifflin-St Jeor equation uses different constants for males and females.
cm
kg
Moderately active: structured exercise around 3–5 days per week.
Moderate: approximately 20% deficit from estimated maintenance.
Your data is calculated in your browser and is never stored.
2

Your Results

Your personalised targets

Enter your details and select Calculate My Calories to estimate your BMR, maintenance calories and goal-specific calorie target.

CALCULATOR METHODOLOGY

How Does the Calorie Calculator Work?

The calculator first estimates the amount of energy your body uses at rest, adjusts this estimate for your activity level, and then applies a calorie adjustment based on your selected goal. The result provides a practical starting estimate rather than a direct measurement of your metabolism.

01

Estimate Resting Energy

Your age, sex, height and body weight are entered into the Mifflin-St Jeor equation to estimate your resting energy expenditure.

02

Estimate Daily Expenditure

Your resting energy estimate is multiplied by an activity factor to estimate your Total Daily Energy Expenditure, commonly referred to as TDEE.

03

Apply Your Goal

The calculator then applies your selected maintenance, fat-loss or muscle-gain setting to provide a practical starting calorie target.

Step 1 — Estimating Resting Energy Expenditure

The calculator uses the Mifflin-St Jeor equation, published in 1990, to estimate resting energy expenditure. This represents approximately how much energy your body would require while at rest before normal daily activity and exercise are taken into account.

Male Equation
(10 × weight in kg)
+ (6.25 × height in cm)
− (5 × age in years)
+ 5
Female Equation
(10 × weight in kg)
+ (6.25 × height in cm)
− (5 × age in years)
− 161
Weight Kilograms
Height Centimetres
Age Years
Result kcal per day

BMR or Resting Energy Expenditure?

For simplicity, fitness calculators commonly describe this result as BMR. Technically, the original Mifflin-St Jeor study developed an equation for predicting resting energy expenditure (REE). The terms BMR and RMR are often used interchangeably in consumer calorie calculators, although they are not physiologically identical measurements.

Step 2 — Estimating Total Daily Energy Expenditure

Resting energy expenditure does not include the energy you use through daily movement, work, exercise and other activity. To estimate total daily energy expenditure, the calculator multiplies your resting energy estimate by the activity factor that best represents your typical week.

TDEE Formula Estimated TDEE = Resting Energy Expenditure × Activity Factor
Activity Level Factor Typical Activity
Sedentary 1.20 Little structured exercise and a predominantly sedentary lifestyle.
Lightly Active 1.375 Light exercise or sport approximately 1–3 days per week.
Moderately Active 1.55 Structured moderate exercise approximately 3–5 days per week.
Very Active 1.725 Hard exercise approximately 6–7 days per week and/or a relatively active lifestyle.
Extremely Active 1.90 Very high training volumes, demanding daily physical activity and/or a physically intensive job.
Important: Activity factors are broad estimation tools rather than precise measurements of energy expenditure. They were not part of the original Mifflin-St Jeor equation. Two people selecting the same activity category may still have substantially different energy requirements due to differences in daily steps, occupation, training volume, exercise intensity and non-exercise activity.

Step 3 — Adjusting Calories for Your Goal

Once estimated maintenance calories have been calculated, the calculator applies your selected goal and pace. These goal adjustments are practical planning settings used by this calculator and are separate from the Mifflin-St Jeor equation itself.

Fat-Loss Targets

Conservative −10%
Moderate −20%
High −30%

Muscle-Gain Targets

Conservative +5%
Moderate +10%
High +15%
Higher is not automatically better. A larger calorie deficit may increase the rate of weight loss, but it can also make hunger, recovery, training performance and lean-mass retention more difficult. Likewise, larger calorie surpluses do not necessarily produce proportionally greater muscle growth and may increase fat gain. Your appropriate target depends on your starting point, goals, training status and individual response.

Why Your Real-World Results Still Matter

No calorie equation can measure your true daily energy expenditure from a few inputs alone. The result should therefore be treated as a starting estimate. Follow your calculated target consistently, monitor average body-weight trends and training performance for approximately 2–3 weeks, and adjust your calorie intake if your progress does not match your intended goal.

What Can Affect Your Actual Calorie Needs?

Differences in body composition, daily step count, non-exercise activity, occupation, training volume, exercise intensity, food intake, metabolic adaptation and individual physiology can all cause actual energy expenditure to differ from the calculator estimate.

Primary equation reference: Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition. 1990;51(2):241–247.

HOW IS THIS CALCULATED?

We use the Mifflin-St Jeor Equation to estimate your Basal Metabolic Rate (BMR), then adjust for your activity level to estimate Total Daily Energy Expenditure (TDEE).

From there, we apply calorie adjustments based on your goal to give you personalized calorie targets.

.

HOW TO USE YOUR RESULTS?

CHOOSE YOUR TARGET

Use the calorie target that aligns with your goal.

TRACK & ADJUST

Monitor your progress for 2-3 weeks and adjust calories if needed.

BE CONSISTENT

Consistent nutrition and training is the key to long-term results.

OTHER FREE CALCULATORS

Other free calculators to support your goals.

Calorie Calculator

Estimate your daily calorie needs based on your goals, activity level and body stats.

Macro Calculator

Get personalised macro targets for fat loss, muscle gain or maintenance.

Protein Calculator

Find your ideal daily protein intake based on your body status and training goals

Body Fat Calculator

Estimate your body fat percentage using simple measurements.

1RM Strength Calculator

Calculate your one-rep max for any lift based on reps and weight lifted

Cardio Training Calculator

Calculate your personal cardio training zones of differing intensities

FREQUENTLY ASKED QUESTIONS

Why is my activity level important?2026-07-06T21:36:07+01:00

Activity level helps estimate how many calories you burn above resting needs. Choosing too high or too low can shift your target significantly.

How accurate is this calorie calculator?2026-07-06T21:34:54+01:00

This calculator gives an evidence-based estimate, but your true maintenance can vary depending on steps, training, tracking accuracy, digestion, sleep and stress.

What if my weight loss stalls?2026-07-06T21:37:54+01:00

If your weight has not changed for 2–3 weeks, review tracking accuracy, steps and training consistency before adjusting calories.

How often should I recalculate?2026-07-06T21:37:06+01:00

Recalculate after a meaningful bodyweight change, activity change, or after 3–4 weeks of progress tracking.

Want a fully personalised plan?

Get a tailored nutrition and training plan designed around your body, goals and lifestyle.

Go to Top