How Many Calories Should I Eat Per Day?

Q: How many calories should I eat to lose 1 kg per week?

Losing 1 kg per week requires a daily deficit of approximately 1,100 kcal. This is aggressive and risks muscle loss. A more sustainable approach is 0.5 kg per week using a 500-550 kcal daily deficit. Calculate your TDEE first, then subtract 500 kcal.

Q: Why am I not losing weight in a calorie deficit?

The most common reasons are: underestimating food portions (people underestimate by 20-40%), overestimating activity level, water retention masking fat loss, and metabolic adaptation. Assess weight trends over 3-4 weeks rather than day-to-day.

How many calories you should eat per day depends on your age, sex, height, weight, and how active you are. There is no single correct answer — but there is a scientifically validated formula that gets you very close. This guide explains the Mifflin-St Jeor method and how to use your result to reach your goal.

The Short Answer — Average Daily Calorie Needs

General guidelines from major health organisations provide these rough daily targets for maintenance (neither gaining nor losing weight):

Group	Sedentary	Moderately Active	Very Active
Women (19–50)	1,600–1,800 kcal	1,800–2,200 kcal	2,000–2,400 kcal
Women (51+)	1,600 kcal	1,800 kcal	2,000–2,200 kcal
Men (19–50)	2,000–2,400 kcal	2,400–2,800 kcal	2,800–3,200 kcal
Men (51+)	2,000 kcal	2,200–2,400 kcal	2,400–2,800 kcal

These are population averages — individual needs can vary by 20–30% from these figures. The formula below gives you a personalised estimate.

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How to Calculate Your Personal Calorie Needs

The most accurate method for estimating daily calorie needs uses a two-step process: first calculate your Basal Metabolic Rate (BMR), then adjust for activity level to get your Total Daily Energy Expenditure (TDEE).

Step 1 — Calculate Your BMR

Your Basal Metabolic Rate is the number of calories your body burns at complete rest — just to keep your heart beating, lungs breathing, and organs functioning. The Mifflin-St Jeor equation is the most accurate formula currently available for estimating BMR in the general population:

Mifflin-St Jeor Equation

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

Example — 35-year-old woman, 165 cm, 65 kg:
BMR = (10 × 65) + (6.25 × 165) − (5 × 35) − 161 = 650 + 1031.25 − 175 − 161 = 1,345 kcal/day

Step 2 — Multiply by Your Activity Level (TDEE)

Your BMR represents calories burned at rest. To find your actual daily needs, multiply by an activity factor:

Activity Level	Multiplier	Description
Sedentary	× 1.2	Desk job, little or no exercise
Lightly active	× 1.375	Light exercise 1–3 days/week
Moderately active	× 1.55	Moderate exercise 3–5 days/week
Very active	× 1.725	Hard exercise 6–7 days/week
Athlete	× 1.9	Physical job or 2× daily training

Continuing the example: If our 35-year-old woman is moderately active, her TDEE = 1,345 × 1.55 = 2,085 kcal/day. This is her maintenance level — eating this amount should keep her weight stable.

Adjusting Calories for Your Goal

Lose Weight

Subtract 300–500 kcal/day from TDEE. Expect to lose approximately 0.3–0.5 kg per week.

Maintain Weight

Eat at your TDEE. Weight should remain stable over time with normal fluctuations.

Gain Muscle

Add 200–300 kcal/day above TDEE. Aim for slow, lean muscle gain with adequate protein.

Important safety note: Never eat below 1,200 kcal/day (women) or 1,500 kcal/day (men) without medical supervision. Very low calorie diets cause muscle loss, nutrient deficiencies, and metabolic adaptation that makes long-term weight maintenance harder.

Calorie Needs by Age

Calorie needs change significantly throughout life. Metabolism naturally slows with age — largely due to gradual muscle loss (sarcopenia) — meaning older adults need fewer calories to maintain the same weight:

Age Group	Women (Sedentary→Active)	Men (Sedentary→Active)
19–25	2,000–2,400 kcal	2,400–3,000 kcal
26–35	1,800–2,400 kcal	2,400–3,000 kcal
36–50	1,800–2,200 kcal	2,200–2,800 kcal
51–65	1,600–2,200 kcal	2,000–2,600 kcal
66–75	1,600–2,000 kcal	2,000–2,400 kcal
76+	1,600 kcal	2,000 kcal

Why do calorie needs decrease with age? Muscle tissue burns approximately 3× more calories at rest than fat tissue. As adults lose 3–8% of muscle mass per decade after age 30, basal metabolic rate declines proportionally. Strength training is the most effective way to slow this metabolic decline.

Calorie Needs for Weight Loss

A sustainable calorie deficit for weight loss is 300–500 kcal below your TDEE per day. This creates a weekly deficit of 2,100–3,500 kcal, corresponding to approximately 0.3–0.5 kg (0.6–1 lb) of weight loss per week.

Larger deficits (500–750 kcal/day) can produce faster weight loss of 0.5–0.75 kg per week, but carry higher risks of muscle loss, fatigue, and nutritional deficiencies. Deficits above 1,000 kcal/day should only be undertaken with medical supervision.

Why the Calorie Deficit Slows Over Time

As you lose weight, your maintenance calories decrease because a lighter body burns fewer calories at rest and during activity. This is why weight loss typically plateaus after several weeks — not because the approach has stopped working, but because the deficit has shrunk as your body weight has fallen. Recalculate your TDEE every 4–6 weeks and adjust your intake accordingly.

Calorie Needs for Muscle Building

Building muscle requires a calorie surplus — eating more than your TDEE. However, the optimal surplus for lean muscle gain is smaller than many people assume:

Beginners (first 1–2 years of training): 200–300 kcal/day surplus, with gains of 0.5–1 kg muscle per month possible
Intermediate (2–5 years): 200 kcal/day surplus; gains slow to 0.2–0.5 kg per month
Advanced (5+ years): Very small surpluses; muscle gain slows significantly regardless of approach

Protein intake is as important as total calories for muscle building. Aim for 1.6–2.2 g of protein per kg of body weight per day when training for muscle gain.

How Accurate Are Calorie Calculations?

The Mifflin-St Jeor equation is the most accurate of the commonly used BMR formulas, but individual metabolic rates can vary by up to ±10% from predicted values even in healthy adults. Activity multipliers are also approximations — most people overestimate their activity level, which is the most common reason TDEE calculations don’t match real-world results.

The most reliable approach: Use the calculated TDEE as your starting point. Track your actual body weight daily for 2–3 weeks. If weight is stable, you are at maintenance. If weight is rising, reduce by 100–200 kcal. If falling faster than desired, increase by 100–200 kcal. Real-world data beats any formula.

What About Calorie Labels on Food?

Food calorie labels are permitted to be inaccurate by up to 20% in either direction in the United States and EU. Restaurant meals can vary even more significantly — studies have found actual calorie content in restaurant meals differing from stated values by 100–300 kcal in either direction.

This is another reason why tracking trends in body weight over time is more reliable than precise calorie counting. A 100–200 kcal error in your daily tracking is normal and unavoidable.

Frequently Asked Questions

How many calories should I eat to lose 1 kg per week?

Losing 1 kg per week requires a daily calorie deficit of approximately 1,100 kcal (since 1 kg of body fat contains roughly 7,700 kcal). For most people, this is an aggressive deficit that risks muscle loss and is difficult to sustain. A more sustainable approach is 0.5 kg per week (deficit of ~550 kcal/day), which preserves more muscle mass and is much easier to maintain. Calculate your TDEE first using our calorie calculator, then subtract 500–550 kcal for a 0.5 kg/week target.

How many calories does 10,000 steps burn?

10,000 steps burns approximately 300–500 kcal for most adults, depending on body weight, walking speed, and terrain. A heavier person burns more calories walking the same distance because more energy is required to move a larger mass. As a rough guide: 100 steps burns approximately 3–5 kcal, so 10,000 steps ≈ 300–500 kcal. This is already factored into your TDEE if you selected the appropriate activity level.

Do I need to count calories to lose weight?

No — calorie counting is one approach but not the only one. Many people successfully lose weight through portion control, eating more protein and fibre (both increase satiety), reducing ultra-processed foods, and following time-restricted eating. However, understanding approximately how many calories you need provides useful context even if you do not track every gram. Studies suggest that people who are at least aware of calorie content make better food choices even without strict tracking.

Why am I not losing weight in a calorie deficit?

The most common reasons: (1) Underestimating food portions — studies show people consistently underestimate calorie intake by 20–40%; (2) Overestimating activity — activity multipliers often result in TDEE overestimates; (3) Water retention masking fat loss — sodium, carbohydrate intake, and hormonal factors cause daily weight fluctuations of 1–2 kg that can obscure fat loss trends; (4) Metabolic adaptation — the body partially compensates for calorie restriction by reducing non-exercise activity. Weigh yourself at the same time daily and assess the trend over 3–4 weeks, not day-to-day.

How many calories should I eat on rest days?

On rest days, your energy needs are slightly lower — typically 200–400 kcal less than training days, depending on exercise intensity. Many people eat the same amount every day for simplicity, which works fine. If you prefer to cycle calories, eating slightly less on rest days and slightly more on training days (calorie cycling) can improve energy and performance while maintaining the same weekly average.

The Bottom Line

Your daily calorie needs are determined by your BMR (calculated using the Mifflin-St Jeor equation) multiplied by your activity level. For most adults, maintenance calories range from 1,600–2,000 kcal for women and 2,000–2,600 kcal for men depending on size and activity.

To lose weight sustainably, aim for a deficit of 300–500 kcal below your TDEE. To build muscle, add 200–300 kcal above it. Adjust every 4–6 weeks based on real-world results — no formula is perfectly accurate for every individual.

Get your exact TDEE in seconds — personalised to your age, sex, height, weight and activity level.

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ⓘ Medical Disclaimer The information in this article is intended for general educational purposes only and does not constitute medical advice, diagnosis, or treatment. Results from our calculators are estimates based on population-level formulas and may not reflect your individual circumstances. Always consult a qualified healthcare professional before making changes to your diet, exercise routine, or health management plan.