Calorie & Macro Calculator — How Many Calories Should You Eat Per Day?

What Is a Calorie & Macro Calculator?

A calorie and macro calculator is a free online tool that tells you exactly how many calories, grams of protein, carbohydrates, and fats your body needs every single day — based on your age, height, weight, activity level, and personal goal.

Whether you want to lose weight, build muscle, or simply maintain a healthy weight, knowing your daily calorie and macronutrient targets is the single most important step you can take toward real, lasting results.

Use the free calorie and macro calculator above to get your personalised numbers in under 60 seconds.

How Many Calories Should I Eat Per Day?

This is one of the most searched questions in health and nutrition — and the honest answer is: it depends on you.

According to the Dietary Guidelines for Americans, adult females typically require between 1,600 and 2,400 calories per day, while adult males need between 2,200 and 3,000 calories. However, this varies significantly depending on age, height, weight, lifestyle, and activity level.

That wide range is exactly why a personalised calculator matters. Two 30-year-old women of the same weight can have vastly different calorie needs depending on whether one is a desk worker and the other is a personal trainer.

Factors that determine your daily calorie needs:

• Age — metabolism slows gradually after your mid-20s
• Gender — men generally burn more calories due to greater muscle mass
• Height and weight — larger bodies require more energy to function
• Activity level — the biggest variable. A sedentary person can need 700+ fewer calories per day than a very active one
• Goal — losing fat, maintaining weight, and building muscle all require different calorie targets

What Is BMR? (Basal Metabolic Rate Explained)

Your BMR (Basal Metabolic Rate) is the number of calories your body burns just to stay alive — breathing, circulating blood, regulating temperature, and keeping your organs functioning — when you are completely at rest.

Think of it as the minimum energy your body needs to survive if you stayed in bed all day.

Our calculator uses the Mifflin-St Jeor equation, which is the most clinically validated and widely recommended formula for calculating BMR:

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

Roughly two-thirds of the calories you need each day go into keeping your body running — powering your organs, brain, and basic functions. The remainder goes into fuelling movement and exercise.

What Is TDEE? (Total Daily Energy Expenditure)

Once you have your BMR, you need to account for how active you actually are. This gives you your TDEE — Total Daily Energy Expenditure — which is the true number of calories your body burns every day.

TDEE represents the total number of calories your body burns in a 24-hour period. It accounts for your Basal Metabolic Rate, the thermic effect of food (energy used to digest meals), and all physical activity from walking to intense training.

Your TDEE is calculated by multiplying your BMR by an activity factor:

Your TDEE = your maintenance calories. Eating at this level means your weight stays the same. Eat below it to lose weight. Eat above it to build muscle.

Daily Calorie Targets by Goal

Calorie Intake for Weight Loss

To lose weight sustainably, you need to eat fewer calories than your TDEE — creating a calorie deficit.

Research has established that a deficit of 300 to 500 calories per day is the optimal range for sustainable fat loss, translating to approximately 0.25 to 0.5 kg (0.5 to 1 pound) of weight loss per week.

Eating drastically below your needs — under 1,200 calories for women or 1,500 for men — can trigger metabolic adaptation, muscle loss, and nutrient deficiencies, making long-term success much harder.

Recommended approach: Start with a 500-calorie daily deficit (your TDEE minus 500). This is safe, sustainable, and produces predictable results without triggering hunger hormones or slowing your metabolism.

Calorie Intake to Maintain Weight

Eating at your exact TDEE keeps your weight stable. This is also called eating at maintenance and is the ideal starting point before a cut or bulk, as it lets you understand your baseline hunger and energy levels.

Calorie Intake for Muscle Gain

Building muscle requires a calorie surplus — eating slightly more than your TDEE to give your body the extra energy needed for muscle protein synthesis.

For muscle gain, a surplus of 200–350 calories per day minimises unnecessary fat accumulation while providing the energy needed to build lean mass effectively.

What Are Macros? (Macronutrients Explained Simply)

Macros is short for macronutrients — the three main nutrients your body uses for energy: protein, carbohydrates, and fats. Every calorie you eat comes from one of these three.

Understanding your macros matters because two people can eat the same number of calories but get completely different results based on how those calories are split. A calorie is not just a calorie when it comes to body composition.

Protein — 4 calories per gram

Protein is the most important macro for body composition. It builds and repairs muscle tissue, keeps you full longer, has the highest thermic effect (your body burns more calories digesting it), and helps preserve lean muscle during weight loss.

Recommended daily intake:

• Weight loss: 1.6–2.2g per kg of bodyweight
• Muscle gain: 1.8–2.5g per kg of bodyweight
• Maintenance: 1.2–1.6g per kg of bodyweight

Best sources: chicken breast, eggs, Greek yoghurt, cottage cheese, tofu, lentils, fish, whey protein

Carbohydrates — 4 calories per gram

Carbohydrates are your body’s and brain’s preferred fuel source. They power your workouts, support thyroid function, and maintain serotonin levels — which directly affects mood and sleep quality.

The key is choosing complex, fibre-rich carbohydrates over refined ones: oats, brown rice, sweet potatoes, legumes, fruits, and vegetables rather than white bread, pastries, or sugar-sweetened drinks.

Recommended daily intake: 40–50% of total calories for most active people

Fats — 9 calories per gram

Dietary fat is essential for hormone production (including testosterone and oestrogen), brain health, fat-soluble vitamin absorption (vitamins A, D, E, K), and joint health. Fat is not the enemy — the right kinds of fat are crucial for wellbeing.

Your daily fat intake should generally account for at least 15–20% of total calories. Dropping below this level can lead to dry skin, hair loss, weakened immunity, and vitamin deficiency issues.

Best sources: avocado, olive oil, nuts, seeds, oily fish (salmon, mackerel), eggs, dark chocolate

Recommended Macro Splits by Goal

These are the macro ratios our calculator uses — based on widely accepted sports nutrition guidelines for each goal type. They are starting points: adjust based on how your body responds over 2–4 weeks.

How to Use Your Calorie and Macro Results

Getting your numbers is step one. Putting them into practice is what creates results.

Step 1 — Use the calculator above Enter your age, gender, height, weight, activity level, and goal. Your personalised calorie target and macro breakdown appear instantly.

Step 2 — Track your food for 2 weeks Use a free app like MyFitnessPal or Cronometer to log everything you eat. You do not need to track forever — just long enough to understand what your current diet looks like versus your targets.

Step 3 — Adjust every 3–4 weeks As your weight changes, your BMR and TDEE shift with it. Recalculate every month to keep your targets accurate. Use the calculator at the top of this page any time.

Step 4 — Prioritise protein first Hit your protein target every day before worrying about carbs and fats. Protein is the most important macro for both fat loss and muscle gain, and most people consistently under-eat it.

Step 5 — Be consistent, not perfect Hitting within 10% of your calorie and macro targets most days is far more effective than being perfect for two weeks and then giving up. Sustainable habits beat aggressive short-term plans every time.

Common Mistakes When Using a Calorie Calculator

Choosing the wrong activity level. Most people overestimate how active they are. If you exercise 3 times per week but spend the rest of your day sitting at a desk, choose “lightly active” — not “moderately active.” Overestimating activity is the most common reason people don’t lose weight even when they think they’re eating correctly.

Not adjusting as weight changes. As weight decreases, both BMR and TDEE shift downward, meaning the calorie target may need minor adjustments every few weeks to keep progress moving. Recalculate monthly.

Eating too far below your targets. A bigger deficit does not mean faster results. Eating too little causes muscle loss, hormonal disruption, fatigue, and extreme hunger — all of which make you more likely to give up.

Ignoring liquid calories. Coffee with cream, fruit juice, sports drinks, and alcohol contain significant calories that are easy to overlook. Track everything for the most accurate picture.

Frequently Asked Questions

How accurate is a calorie calculator?

Calorie calculators based on the Mifflin-St Jeor equation are accurate within 10–15% for most healthy adults. They are estimates — individual metabolism varies due to genetics, hormones, gut microbiome, and muscle mass. Use your results as a starting point and adjust based on real-world results over 2–4 weeks.

How many calories do I need to lose 1 kg per week?

One kilogram of body fat contains approximately 7,700 calories. To lose 1 kg per week, you would need a daily deficit of around 1,100 calories — which is aggressive and not recommended for most people. A deficit of 500 calories per day (losing roughly 0.5 kg per week) is safer, more sustainable, and better for preserving muscle mass.

Should I eat back the calories I burn during exercise?

Only if you selected “sedentary” as your activity level and are tracking exercise separately. If you chose an activity level that already reflects your exercise habits (moderately active, very active), those calories are already built into your TDEE — do not eat them back.

What is the difference between BMR and TDEE?

BMR is how many calories you burn at complete rest — just to keep your organs working. TDEE includes everything: BMR plus the calories burned through daily movement, exercise, and digesting food. Your TDEE is your true maintenance calorie number.

How often should I recalculate my macros?

Recalculate every 4–6 weeks or whenever your weight changes by more than 3–4 kg. As your body changes, your calorie and macro needs change with it. Bookmark this page and use the calculator monthly to stay on track.

Is it better to count calories or track macros?

Counting calories tells you how much energy you are consuming. Tracking macros tells you where that energy is coming from — and the quality of your food choices. For body composition goals (losing fat or building muscle), tracking macros gives you much more useful information than calories alone.

Related Tools on This Site

• BMI Calculator — find out if your current weight is in a healthy range for your height
• One Rep Max Calculator — calculate your strength levels and plan your lifting programme

The information on this page is for educational purposes only and does not constitute medical or nutritional advice. Please consult a registered dietitian or healthcare professional before making significant changes to your diet.