How to Calculate Calories for Weight Loss

Overview

Calculating calories for weight loss comes down to one core equation: eat fewer calories than your body burns each day. The catch is that most people don't actually know how many calories they burn, and guessing tends to land on either too little progress or a deficit so large it stalls out after a few weeks.

This guide walks through a four-step process: finding your TDEE (the total calories your body uses each day), setting an appropriate deficit, working out macronutrient targets, and adjusting your numbers when progress stalls. By the end you'll have a specific daily calorie target and a way to keep it accurate as your weight changes.

Run your own numbers alongside this guide using the TDEE Calculator and Calorie Calculator.

What You Need

Your current weight in kilograms
Your height in centimetres
Your age in years
An honest read on your weekly activity level
A food tracking app or some method for logging what you eat

Step 1: Calculate Your TDEE

TDEE, Total Daily Energy Expenditure, is what your body burns in a typical day. It comes in two parts: BMR first, then an activity multiplier on top.

Calculate BMR using the Mifflin-St Jeor equation:

Men: BMR = (10 × weight_kg) + (6.25 × height_cm) − (5 × age) + 5
Women: BMR = (10 × weight_kg) + (6.25 × height_cm) − (5 × age) − 161

Mifflin-St Jeor is the most widely recommended formula because it holds up well across a broad range of body types. The older Harris-Benedict formula overestimates BMR by 5 to 15% for most people, so it's best skipped.

Apply your activity multiplier:

Activity Level	Multiplier	Description
Sedentary	1.2	Desk job, no intentional exercise
Lightly active	1.375	Exercise 1–3 days/week
Moderately active	1.55	Exercise 3–5 days/week
Very active	1.725	Hard exercise 6–7 days/week
Extra active	1.9	Physical job + daily training

Most people should start at a slightly lower multiplier than feels right. Underestimating activity is far safer than overestimating it, since overestimation creates a phantom deficit that doesn't actually translate into weight loss.

The TDEE Calculator gets you this number instantly, no manual arithmetic needed.

Step 2: Set a Calorie Deficit

Once you have your TDEE, subtract a specific number of calories to create a deficit:

Moderate deficit (−300 to −500 kcal/day): sustainable, preserves muscle, results in 0.25 to 0.45 kg/week loss. Recommended for most people.
Aggressive deficit (−750 to −1,000 kcal/day): produces 0.7 to 0.9 kg/week but raises muscle loss and hunger. Reserve this for limited periods under medical guidance.

Hard floors, don't go below these:

Women: 1,200 kcal/day
Men: 1,500 kcal/day

Cross those thresholds and you risk metabolic adaptation: the body lowers TDEE in response to severe restriction by cutting spontaneous movement, lowering body temperature, and slowing metabolic processes. That makes sustained weight loss progressively harder, not easier.

A rate of 0.5 to 1% of bodyweight per week is generally considered safe and sustainable. For a 70 kg person, that's 0.35 to 0.7 kg per week.

Step 3: Calculate Protein, Carb, and Fat Targets

Your calorie target is only part of the picture. Macronutrient distribution determines how much of the weight you lose is fat versus muscle.

Set protein first. Research consistently shows higher protein intake during a deficit preserves lean muscle mass. Target 1.6 to 2.2 g per kg of bodyweight. For a 70 kg person, that's 112 to 154 g of protein a day. Protein provides 4 kcal per gram, so 130 g works out to 520 kcal.

Set fat second. Fat is essential for hormone production and absorbing fat-soluble vitamins. Keep it at a minimum of 0.7 g per kg of bodyweight, at least 49 g a day for a 70 kg person. Fat provides 9 kcal per gram, so 49 g comes to 441 kcal.

Fill the rest with carbohydrates. Carbs provide 4 kcal per gram and are the preferred fuel for high-intensity exercise. Subtract protein and fat calories from your daily target to find your carb allowance.

Worked example: 70 kg woman, TDEE 2,200 kcal, 500 kcal deficit, 1,700 kcal target:

Protein: 130 g × 4 = 520 kcal
Fat: 55 g × 9 = 495 kcal
Carbs: (1,700 − 520 − 495) / 4 = 171 g

Step 4: Track Daily Intake

Tracking food intake is arguably the single highest-leverage habit for weight loss success. People who track what they eat consistently lose more weight than those who don't.

Key tracking rules:

Weigh food raw, or at least note whether you're using cooked weights. 100 g of raw chicken has more protein and calories than 100 g of cooked chicken, because water evaporates during cooking.
Log everything. Cooking oils, dressings, milk in coffee, and calorie-containing drinks are the items people forget most. A tablespoon of olive oil is 120 kcal; a flat white is 100 to 150 kcal.
Don't rely on memory. Log at the time of eating, not at the end of the day. End-of-day logging misses an average of 400 to 500 kcal in research studies.
The Calories Burned Calculator helps estimate exercise output if you want to track your net balance.

Step 5: Adjust After 2–3 Weeks

Your initial calorie target is just an estimate. Real-world results tell you whether it's accurate. After 2 to 3 weeks of consistent tracking:

No weight loss: drop your daily target by 100 to 200 kcal and continue another 2 weeks before reassessing.
Losing too fast (more than 1% bodyweight/week): raise your target by 100 to 150 kcal to slow the rate and reduce muscle loss.
Progress stalls after an early drop: recalculate TDEE using your new, lower bodyweight. As you lose weight, BMR falls and maintenance calories drop with it. A 10 kg loss typically knocks 150 to 250 kcal off TDEE.

Plan to recalculate TDEE and update your target after every 5 kg of weight loss.

Common Mistakes to Avoid

Cutting too aggressively from day one. Starting with a 1,000 kcal deficit feels fast, but it usually leads to muscle loss, extreme hunger, and eventual rebound. A 500 kcal deficit gets you meaningful progress while staying sustainable for months, not weeks.

Ignoring liquid calories. Juice, soft drinks, alcohol, sports drinks, and calorie-heavy coffee beverages stay invisible in most food diaries unless you deliberately track them. A single glass of orange juice (200 ml) runs about 90 kcal; two beers add 300. These add up fast without ever making you feel full.

Not accounting for exercise adaptation. After 6 to 8 weeks of regular training, the body gets more efficient at the same movements, burning fewer calories for the same workout. Progressive overload, more weight, intensity, or volume over time, is what keeps calorie expenditure from exercise from flatlining.

Failing to recalculate as weight drops. A 90 kg person who loses 15 kg needs roughly 200 to 250 fewer daily calories at 75 kg to maintain the same rate of loss. Sticking with the original TDEE too long creates a smaller actual deficit than intended, which is exactly why progress often slows after the first month or two.

Using bathroom scales only. Daily weight swings 1 to 3 kg from water, food mass, glycogen, and hormonal variation. Track a 7-day or 14-day rolling average instead of individual daily readings. The BMI Calculator gives some context for where your current weight sits relative to healthy ranges.

Formula & Methodology

Mifflin-St Jeor BMR:

Men: BMR = (10 × weight_kg) + (6.25 × height_cm) − (5 × age) + 5
Women: BMR = (10 × weight_kg) + (6.25 × height_cm) − (5 × age) − 161

TDEE: TDEE = BMR × Activity Multiplier

Calorie target: Daily Target = TDEE − Deficit

Worked example: 30-year-old woman, 70 kg, 165 cm, moderately active:

BMR = (10 × 70) + (6.25 × 165) − (5 × 30) − 161
BMR = 700 + 1,031 − 150 − 161 = 1,420 kcal
TDEE = 1,420 × 1.55 = 2,201 kcal
500 kcal deficit: Daily target = 1,701 kcal

This target produces roughly 0.45 kg of weight loss per week, about 2 kg a month, a safe and sustainable rate that minimises muscle loss when paired with enough protein.