Mealiv
Calorie Calculator
Estimate how many calories you need each day to maintain, lose or gain weight. Mealiv’s free calorie calculator uses the Mifflin–St Jeor equation to estimate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE), giving you a personalised daily calorie target in seconds.
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Your daily calorie targets
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Generate personalised meal plans, shopping lists and nutrition insights in minutes — all built around the calorie number above.
Build my meal plan freeFind your daily calorie needs
Use the calculator above to estimate:
- Maintenance calories
- Calories for weight loss
- Calories for muscle gain
- Your estimated BMR
- Your estimated TDEE
Simply enter your age, sex, height, weight and activity level to receive an instant estimate.
What is a calorie?
A calorie is a unit of energy. Every food and drink you consume provides calories, while your body burns calories throughout the day to power essential functions such as breathing, digestion, circulation and movement.
Your body burns calories even when you’re asleep. The number of calories you need each day depends on factors including age, sex, height, weight, muscle mass, activity level and overall health.
Eating more calories than you burn generally leads to weight gain, while eating fewer calories than you burn creates a calorie deficit that can result in weight loss.
How many calories do I need each day?
There is no single answer because everyone is different. As a rough guide:
| Person | Approximate daily calories |
|---|---|
| Adult women | 1,600–2,400 kcal |
| Adult men | 2,000–3,000 kcal |
However, these figures are only averages. Someone who is 6 ft 4, highly active and lifts weights several times per week may need well over 3,500 calories per day, while someone with a sedentary lifestyle may require considerably fewer.
That’s why a personalised calorie calculator provides a much more useful estimate than relying on population averages.
How your daily target is built
Four steps turn your body measurements into a calorie goal:
- BMRWhat your body burns at rest
- × Activity multiplier1.2 sedentary → 1.9 very active
- = TDEEYour maintenance calories
- ± Goal adjustment−500 to lose, +250 to gain
What is BMR?
Basal Metabolic Rate (BMR) is the number of calories your body requires simply to stay alive. Your BMR covers breathing, maintaining body temperature, circulation, brain function, cell repair and organ function.
For most people, BMR accounts for around 60–70% of total daily calorie expenditure. You would still burn these calories even if you stayed in bed all day.
What is TDEE?
Total Daily Energy Expenditure (TDEE) is the total number of calories you burn each day. It includes your BMR plus walking, exercise, household activities, standing and digestion (the thermic effect of food).
Your TDEE represents your maintenance calories. If you eat approximately this number of calories over time, your weight should remain relatively stable.
Calorie needs by activity level
The activity multiplier applied to your BMR makes a substantial difference:
| Activity level | Typical week | Multiplier |
|---|---|---|
| Sedentary | Desk job, little or no exercise | × 1.2 |
| Lightly active | Light exercise 1–3 days | × 1.375 |
| Moderately active | Moderate exercise 3–5 days | × 1.55 |
| Very active | Hard exercise 6–7 days | × 1.725 |
| Extra active | Physical job or twice-daily training | × 1.9 |
Calories for weight loss
To lose weight, you generally need to create a calorie deficit. Many people begin with a deficit of around 250 to 500 calories per day.
A moderate calorie deficit can help you lose body fat gradually, preserve muscle more effectively, feel fuller than with extreme diets, and build sustainable eating habits.
Mealiv automatically estimates an appropriate calorie target for gradual weight loss based on your maintenance calories. If you’d like to see what that looks like as real meals, our 1,500 calorie meal plan and 1,200 calorie meal plan are worked examples.
Calories for muscle gain
Building muscle usually requires a calorie surplus combined with resistance training and sufficient protein intake.
A moderate surplus of around 250–500 calories above maintenance is commonly recommended to support muscle growth while limiting unnecessary fat gain.
Mealiv can help you combine your calorie target with personalised protein goals and meal planning — start with the protein calculator, then see how to hit your protein goals every day.
Why calorie quality matters
Calories are important, but food quality matters too. Two meals may each contain 500 calories but provide very different nutritional value.
A balanced diet should include lean protein, wholegrains, fruit, vegetables, healthy fats, fibre, and vitamins and minerals.
Mealiv doesn’t just help you count calories — it also tracks protein, carbohydrates, fats, fibre, vitamins and minerals so you can improve your overall nutrition, not just your energy intake. You can check any dish with the recipe nutrition calculator.
What affects calorie requirements?
Many factors influence how many calories your body burns each day, including age, sex, body size, muscle mass, exercise habits, occupation, genetics and hormonal changes.
This is why calorie needs change over time, and why it’s useful to recalculate whenever your weight or activity level changes.
Why use Mealiv?
Knowing your calorie target is only the first step. Mealiv helps you put those numbers into practice by allowing you to:
- Track calories automatically
- Log meals with AI
- Scan food barcodes
- Build personalised meal plans
- Calculate recipe nutrition
- Track protein, carbs and fat
- Monitor vitamins and minerals
- Analyse your diet over time
- Receive AI-powered nutrition insights
Instead of simply telling you how many calories to eat, Mealiv helps you consistently achieve your nutrition goals.
How this is calculated
Daily calorie needs are estimated using the Mifflin–St Jeor BMR equation — the most accurate published BMR estimator for healthy adults — multiplied by an activity factor (1.2 sedentary → 1.9 very active). The resulting Total Daily Energy Expenditure (TDEE) is what you need to maintain your current weight; we subtract 500 kcal/day for moderate weight loss (≈0.5 kg/week, the NHS-recommended sustainable rate) and add 250–500 kcal/day for muscle gain.
Men: BMR = 10·W + 6.25·H − 5·age + 5 · Women: BMR = 10·W + 6.25·H − 5·age − 161 · TDEE = BMR × activity
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How this calculator works
This calculator uses the Mifflin-St Jeor equation to estimate your Basal Metabolic Rate (BMR) — the calories your body needs at rest. It then applies an activity multiplier to estimate your total daily energy expenditure (TDEE).
The deficit and surplus targets are simple adjustments from your maintenance level. A 500-calorie deficit is a common starting point for gradual weight change.
Frequently asked questions
How many calories do I need per day?
Daily calorie needs depend on your age, sex, height, weight, and activity level. Most adults need between 1,600 and 3,000 calories per day. Use the calculator above to estimate your specific needs.
What is BMR?
BMR (Basal Metabolic Rate) is the number of calories your body burns at rest to maintain basic functions like breathing and circulation. Your total daily calorie needs are higher because they include activity.
How do I lose weight with a calorie deficit?
A calorie deficit means eating fewer calories than your body uses. A 500-calorie daily deficit is a common starting point. Use this calculator to find your maintenance calories, then subtract 250 to 500.
What formula does this calculator use?
This calculator uses the Mifflin-St Jeor equation, which is widely used for estimating BMR. It factors in sex, age, height, and weight, then applies an activity multiplier.
How accurate is this calorie calculator?
The calculator uses the Mifflin–St Jeor equation, one of the most widely accepted methods for estimating calorie requirements in healthy adults. Individual metabolism varies, so results should be treated as estimates rather than exact values.
Should I eat exactly my calorie target?
Your calorie target is an average. Daily intake will naturally vary, and consistency over weeks is generally more important than hitting the exact number every day.
Is calorie counting necessary?
Not necessarily. Some people prefer portion control or intuitive eating. However, calorie tracking can be a useful educational tool if you’re aiming to lose weight, gain muscle or better understand your eating habits.
How often should I recalculate?
Recalculate whenever your weight changes significantly, your activity level changes, or your fitness goals change.
Does Mealiv track calories automatically?
Yes. Mealiv can calculate calories from recipes, scan barcodes, analyse meals from photos, log food using AI, and automatically track your daily calorie intake alongside your protein, carbohydrates, fats and micronutrients.
Start tracking your calories
Log meals, scan barcodes, and see your daily calorie intake update in real time with Mealiv.
Start tracking freeImportant information
The calorie estimates provided by this calculator and by Mealiv are for informational purposes only and do not constitute medical advice. Results are based on general formulas and may not reflect your individual metabolic needs.
Before starting a calorie deficit diet or making significant changes to your eating habits, you should consult a qualified healthcare professional, particularly if you have any existing medical conditions, are pregnant, or are under 18.