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Find your BMR, TDEE and daily calorie target in seconds
Knowing how many calories your body needs is the starting point for any nutrition goal — whether you want to lose weight gradually, maintain your current weight, or support muscle growth. This free calculator uses the Mifflin-St Jeor equation, one of the most widely referenced formulas in nutrition research, to estimate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE).
Your BMR is the number of calories your body burns at complete rest — the minimum energy needed to keep your organs functioning. Your TDEE accounts for how active you are on top of that baseline, giving you a realistic daily calorie number. From there, you apply a small surplus or deficit depending on your goal.
Bear in mind that all calorie calculators produce estimates, not precise prescriptions. Individual metabolic rates vary based on factors like muscle mass, hormonal status, stress levels and gut health that no formula can capture. Use the result as a starting point and adjust by 100–200 kcal based on your real-world progress over 3–4 weeks.
Want a simple plan based on your calorie target? Try the free Meal Plan Generator.
Meal Plan GeneratorThe calculator returns four key numbers. Understanding each one helps you use your result effectively rather than blindly following a single figure:
The macro breakdown (protein, carbs, fat) shown below your calorie target provides a balanced starting split. If you have specific goals like higher protein for muscle building or lower carbs for a keto approach, use our Macro Calculator for a customised split.
Let's walk through a real calculation so you can see exactly how the numbers work:
Profile: Maria, 28 years old, female, 65 kg, 168 cm, moderately active (gym 3× per week), goal: mild weight loss.
At this target, Maria can expect to lose roughly 0.25 kg per week. After 3–4 weeks, she checks: if weight is dropping faster than expected, she adds 100 kcal. If the scale hasn't moved, she subtracts 100–150 kcal. This iterative approach is far more effective than trying to find the "perfect" number on day one.
While this calculator provides a useful starting point, it has inherent limitations that you should be aware of:
Seek professional advice if: your calculated target falls below 1,200 kcal (women) or 1,500 kcal (men), you have a medical condition affecting metabolism, you're pregnant or breastfeeding, you experience persistent fatigue or hair loss on a deficit, or you have a history of disordered eating.
This calculator uses the Mifflin-St Jeor equation, developed in 1990 and widely considered the most accurate predictive formula for estimating resting metabolic rate in healthy adults. The formula calculates your BMR based on weight, height, age and sex, then multiplies by an activity factor to estimate your Total Daily Energy Expenditure (TDEE).
The Mifflin-St Jeor formulas are: Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5. Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161. Your TDEE is then calculated by multiplying your BMR by an activity multiplier ranging from 1.2 (sedentary) to 1.9 (very active).
The largest source of error is the activity multiplier, which depends on self-assessment. Most people tend to overestimate their activity level. If in doubt, select the lower option — it's easier to add calories later than to diagnose why you're not seeing results.
Your BMR (Basal Metabolic Rate) is the energy your body uses just to exist — breathing, keeping your heart beating, maintaining body temperature. For most people this accounts for 60–75% of total daily calorie expenditure.
Your TDEE (Total Daily Energy Expenditure) adds the calories burned through movement, digestion (the thermic effect of food) and non-exercise activity like walking, fidgeting and standing. The activity multiplier applied to your BMR is an estimate — it works well for most people but may need fine-tuning.
For a deeper dive, see our guide: BMR vs TDEE — What's the Difference?
For a detailed breakdown of choosing a realistic deficit size, see our guide: How to Choose the Right Calorie Deficit for Your Body.
Even an accurate calorie target will not produce results if how you use it does not match real life. The most common mistakes are:
The calculator returns an estimate based on population averages. Your actual maintenance may be 10–20% higher or lower. Use the result for 3–4 weeks, then adjust based on your weight trend — not based on what the calculator said on day one.
Most people pick "moderately active" when they should pick "lightly active". Three gym sessions plus a desk job is usually closer to lightly active than moderately active. If unsure, choose the lower option — adding calories later is easier than diagnosing why you are not seeing progress.
Oils, sauces, dressings, creamer in coffee, weekend snacks and restaurant meals are commonly underestimated. Many people who think they eat 1,800 kcal actually average 2,100. If your weight is not changing, tighten tracking before cutting calories further. See Why Weight Loss Stalls Even in a Calorie Deficit for the full plateau checklist.
Going below 1,200 kcal (women) or 1,500 kcal (men) without medical supervision risks muscle loss, fatigue and poor adherence. A moderate deficit you can sustain beats an aggressive deficit you keep breaking.
As your body weight changes, your calorie needs change. Recalculate every 5–10 kg of weight change, or every 8–12 weeks. The target that worked at the start of your weight loss will not match where you are now.
This calculator uses the Mifflin-St Jeor equation, which research suggests is among the more accurate formulas for estimating resting metabolic rate in a general adult population. However, it produces an estimate — individual metabolic rates can vary by ±10–20% from any formula's prediction. Treat the result as a starting point and adjust based on 3–4 weeks of real-world data.
BMR (Basal Metabolic Rate) is the calories your body needs at complete rest to sustain basic functions. TDEE (Total Daily Energy Expenditure) is your BMR multiplied by an activity factor — it represents your actual daily calorie burn, accounting for movement and exercise. Your calorie target is based on your TDEE, not your BMR.
A moderate deficit of 300–500 kcal per day below your TDEE is generally recommended for gradual, sustainable weight loss. This typically results in an estimated 0.3–0.5 kg loss per week. Very large deficits (over 800 kcal) can lead to muscle loss, fatigue and poor adherence, so they are not recommended without medical supervision.
Your TDEE already includes an activity level estimate. If your exercise is already captured by the activity multiplier you selected, you don't need to eat more on training days. If you do very variable training (e.g., mostly sedentary but with one very long run per week), you may want to add back roughly 50–75% of the estimated calories burned during that session.
If the calculator returns a target below 1,200 kcal (women) or 1,500 kcal (men), this is generally considered too low for most healthy adults to meet basic nutritional needs without professional guidance. Consider selecting a smaller deficit goal, or consult a registered dietitian before proceeding.
Yes, but less dramatically than most people assume. Research suggests metabolism decreases by roughly 1–2% per decade after age 20, primarily due to loss of lean muscle mass rather than an inherent metabolic slowdown. This is why the Mifflin-St Jeor formula includes an age variable. Maintaining or building muscle through resistance training is the most effective way to offset age-related metabolic decline. Use our Workout Planner to create a strength routine.
Start by using our Food Search tool to look up the calorie content of foods you eat regularly. For packaged foods, read the nutrition label and note the serving size. You don't need to track perfectly every day — estimating within 100–200 kcal is sufficient for most goals. After 2–3 weeks of practice, most people can estimate portions by eye with reasonable accuracy.
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