Calorie Calculator

How Many Calories Should I Eat?

The number of calories you need each day depends on your age, sex, height, weight, and activity level. Our calorie calculator uses the Mifflin-St Jeor equation to estimate your Total Daily Energy Expenditure (TDEE), then applies goal-based targets.

Calorie Targets by Goal

Goal	Calorie Adjustment	Weekly Change
Lose 1 kg/week	TDEE − 1,000 kcal	−1 kg
Lose 0.5 kg/week	TDEE − 500 kcal	−0.5 kg
Lose 0.25 kg/week	TDEE − 250 kcal	−0.25 kg
Maintain weight	= TDEE	0
Gain 0.25 kg/week	TDEE + 250 kcal	+0.25 kg
Gain 0.5 kg/week	TDEE + 500 kcal	+0.5 kg

What is a Safe Calorie Deficit?

The most sustainable weight loss rate is 0.5–1 kg per week, achieved with a deficit of 500–1,000 kcal/day. Larger deficits risk:

• Loss of muscle mass (especially without adequate protein)
• Nutrient deficiencies
• Metabolic adaptation (your body adapts to burn fewer calories)
• Rebound weight gain after stopping the diet

Most health organisations recommend not going below 1,200 kcal/day for women and 1,500 kcal/day for men without medical supervision.

Calories and Macronutrients

Calories come from three macronutrients:

Macronutrient	Calories per gram
Carbohydrates	4 kcal/g
Protein	4 kcal/g
Fat	9 kcal/g

For a balanced 2,000 kcal diet at 50% carbs / 25% protein / 25% fat:

• Carbohydrates: 250g
• Protein: 125g
• Fat: 56g

Do Calories from All Foods Count the Same?

Technically yes — a calorie is a unit of energy. However, food quality matters for satiety, nutrient density, and metabolic health. Protein and fibre are the most satiating, helping you feel fuller on fewer calories. Ultra-processed foods tend to be easy to overeat due to low satiety and engineered palatability.

How Often Should I Recalculate?

Recalculate your calorie needs every 4–8 weeks or whenever your weight changes by more than 2–3 kg, your activity level changes significantly, or you plateau in your progress.

The Thermic Effect of Food (TEF)

Not all calories are created equal in terms of metabolic processing. The Thermic Effect of Food (TEF) refers to the energy your body uses to digest, absorb, and metabolise food:

• Protein: 20–35% of calories burned in digestion (the highest of any macro)
• Carbohydrates: 5–10% of calories burned in digestion
• Fat: 0–3% of calories burned in digestion

This means that if you eat 200 kcal of protein, your net intake is approximately 130–160 kcal after the digestion cost is deducted. High-protein diets therefore have an inherent metabolic advantage during calorie deficits — which is why protein targets are the first consideration in any intelligent fat loss plan.

Calories for Muscle Gain

Building muscle requires a caloric surplus — calories above your TDEE — to provide the energy and raw materials (primarily protein) needed for muscle protein synthesis. The optimal approach:

• Lean bulk: +250–350 kcal above TDEE (0.25 kg/week gain, mostly muscle)
• Moderate bulk: +500 kcal above TDEE (0.5 kg/week gain, ~50% muscle/fat)
• Aggressive bulk: +750–1,000 kcal above TDEE (faster weight gain but more fat)

For most natural trainees, a 250–350 kcal surplus with adequate protein (1.6–2.2 g/kg/day) maximises lean mass gain while minimising fat accumulation. Use our Macro Calculator to translate your calorie target into the right protein, carbohydrate, and fat split.

The Role of Diet Breaks and Refeeds

Extended calorie restriction triggers adaptive thermogenesis — your body lowers its metabolic rate and suppresses hunger hormones to conserve energy. Two strategies help manage this:

Diet breaks (2 weeks at maintenance): Research published in Obesity journal found that participants who took planned 2-week breaks at maintenance calories during a 16-week diet lost more fat over the same period than continuous dieters — suggesting that maintenance periods partially restore metabolic rate and hormonal balance.

Refeeds (1 day at maintenance or slight surplus, 1–2 days per week): Particularly useful for those in extended deficits — a higher-carbohydrate day restores glycogen and briefly raises leptin, potentially improving subsequent fat loss adherence.

How to Track Calories Accurately

Calorie tracking accuracy varies widely. Research comparing self-reported intake to doubly-labelled water measurements consistently finds that people underestimate their intake by 20–50%. Common sources of calorie miscounting:

1. Eyeballing portion sizes — scales give 2–4× more accurate measurements than visual estimates

2. Ignoring cooking oils — 1 tablespoon of olive oil is 120 kcal

3. Not tracking drinks — lattes, juices, and alcohol add up quickly

4. Forgetting "bites and tastes" — research shows these can add 100–300 kcal/day

For the first 2–4 weeks of any calorie management plan, weigh foods on a digital kitchen scale and use a reliable nutrition database.

Frequently Asked Questions

How many calories should I eat to lose weight?

Subtract 500 kcal from your TDEE for approximately 0.5 kg/week of weight loss, or 250 kcal for 0.25 kg/week. Most health guidelines recommend not going below 1,200 kcal/day for women or 1,400–1,500 kcal/day for men without medical supervision.

Why am I not losing weight in a calorie deficit?

The most common reasons: (1) underestimated food calories, (2) overestimated activity level in the TDEE calculation, (3) water retention masking fat loss, or (4) metabolic adaptation from prolonged restriction. Reassess after 3–4 weeks of consistent, accurately tracked intake.

Are all calories the same?

For pure weight change, yes — 500 kcal of any food creates the same energy balance. But protein has a higher thermic effect (burns 20–35% in digestion), and whole foods are more satiating than processed foods at equal calories. For body composition and health, food quality matters alongside quantity.

How do I calculate my TDEE from my BMR?

Multiply your BMR by your activity factor: sedentary (×1.2), lightly active (×1.375), moderately active (×1.55), very active (×1.725), extra active (×1.9). Our calculator does this automatically.

Should I eat back exercise calories?

If you used an accurate activity level in your TDEE calculation (which already accounts for your training), you should not eat back exercise calories — those are already included. Only eat back exercise calories if you used a sedentary multiplier and are adding exercise on top.

Related Resources

Related Calculators

• Protein Calculator — Calculate your daily protein requirements.
• Macro Calculator — Determine your optimal macronutrient split.

External Authority Resources

• Harvard T.H. Chan School of Public Health: Science of Calories — Scientific review of energy balance.
• NIH MedlinePlus: Calories and Weight Control — Practical guide to calories and health.

Sources

• Mifflin MD et al. Am J Clin Nutr. 1990;51(2):241-7.
• Hall KD et al. Calorie for Calorie, Dietary Fat Restriction Results in More Body Fat Loss than Carbohydrate Restriction in People with Obesity. Cell Metab. 2015.
• NIH. Healthy Eating for a Healthy Weight. cdc.gov/healthyweight