How Many Calories Should You Eat Per Day?

Calories are the energy your body uses to stay alive, move, exercise, digest food and perform everyday activities.

There is no single calorie target that is right for everyone. Your daily calorie needs depend on factors such as age, sex, body size, activity level and whether you want to maintain, lose or gain weight.

As a broad population-level guide, the NHS uses about 2,000 calories per day for an average woman and 2,500 calories per day for an average man. These numbers are useful reference points, not personalized targets.

For an individual estimate, it is more useful to calculate your resting energy needs and then account for your activity.

How many calories should you eat per day?

Your calorie intake should roughly match your total daily energy expenditure if your goal is to maintain your current weight.

That means:

• eating approximately as much energy as you use tends to support weight maintenance
• consistently eating less energy than you use tends to lead to weight loss
• consistently eating more energy than you use tends to lead to weight gain

Your actual needs can differ substantially from population averages.

Two people of the same age may need very different calorie intakes because of differences in height, weight, body composition, occupation, exercise and general movement throughout the day.

Average daily calorie needs

General calorie recommendations can provide context, but they should not be treated as exact prescriptions.

The 2,000 and 2,500 calorie figures are broad reference values used by the NHS.

They do not mean every woman should eat exactly 2,000 calories or every man exactly 2,500.

A smaller sedentary adult may require considerably less, while a larger or highly active adult may require considerably more.

What determines how many calories you need?

Your daily energy expenditure is influenced by several components.

Resting energy expenditure

Even if you stayed in bed all day, your body would still require energy.

Calories are needed for essential processes such as:

• breathing
• circulation
• maintaining body temperature
• brain and nervous system activity
• organ function
• cellular processes

This baseline energy requirement is commonly estimated using resting metabolic rate, or RMR. (Frankenfield et al.)

Physical activity

Movement can create large differences in calorie needs.

This includes structured exercise such as:

• running
• cycling
• strength training
• swimming
• sports

But exercise is only part of daily activity.

Walking, standing, commuting, housework and physically demanding jobs also contribute to total energy expenditure.

Digestion

Your body also uses energy to digest, absorb and process food.

This is often called the thermic effect of food.

Body size and composition

Larger bodies generally require more energy than smaller bodies.

Body composition matters too. Lean tissue is metabolically active, so two people at the same body weight can have somewhat different energy requirements.

Age

Energy needs can change with age because body composition, activity and other factors may change over time.

Sex

Predictive calorie equations commonly include sex because average body composition and resting energy expenditure differ between males and females.

How to calculate your calorie needs

A practical estimate can be made in two stages:

1. Estimate resting metabolic rate.
2. Adjust that estimate for your activity level.

One commonly used equation is the Mifflin-St Jeor equation, originally developed from measured resting energy expenditure in healthy adults.

Mifflin-St Jeor equation for men

RMR = 10 × weight in kg + 6.25 × height in cm − 5 × age + 5

Mifflin-St Jeor equation for women

RMR = 10 × weight in kg + 6.25 × height in cm − 5 × age − 161

The result estimates the calories your body uses at rest.

It is not yet an estimate of your complete daily calorie requirement.

From RMR to daily calorie needs

To estimate total daily energy expenditure, often abbreviated as TDEE, resting energy expenditure is adjusted to reflect activity.

A simplified approach uses activity multipliers.

These multipliers are approximations rather than precise measurements.

For example, suppose someone has an estimated resting requirement of 1,600 calories per day.

Using a moderate activity multiplier of 1.55:

1,600 × 1.55 = 2,480 calories

Their estimated maintenance intake would therefore be approximately 2,480 calories per day.

The real number may be higher or lower.

What are maintenance calories?

Maintenance calories are the approximate number of calories you can consume while keeping body weight relatively stable over time.

If your estimated TDEE is 2,400 calories, then roughly 2,400 calories per day would be your initial maintenance estimate.

But calorie calculators cannot directly measure your metabolism.

The most useful test is what happens to your weight trend when you consistently eat around that amount.

If your average weight remains broadly stable for several weeks, your intake is probably reasonably close to maintenance.

If your weight trends downward, your actual expenditure may be higher than your intake.

If your weight trends upward, your intake may be higher than your expenditure.

Example calorie calculations

The following examples show why one calorie recommendation cannot fit everyone.

These are illustrative examples only.

Your own estimate should use your actual age, height, weight and activity.

How many calories should you eat to lose weight?

Weight loss requires an energy deficit over time.

In practical terms, this means average calorie intake is lower than average energy expenditure.

For example, if maintenance is approximately 2,400 calories, eating somewhat below 2,400 creates a calorie deficit.

That does not mean the largest possible deficit is the best approach.

Aggressive restriction can make a diet harder to sustain and may make it more difficult to obtain enough protein, fiber, vitamins, minerals and other nutrients.

A moderate deficit is generally easier to maintain.

The NHS, for example, uses a reduction of around 600 calories per day as general guidance for many adults trying to lose weight. Individual requirements can differ, and a personalized target may be more appropriate.

We cover the subject separately in our guide to calorie deficits, because calculating maintenance calories and deciding on an appropriate deficit are related but different questions.

How many calories should you eat to maintain weight?

Start with your estimated TDEE.

Then compare that estimate with real-world results.

A useful approach is:

1. Estimate your maintenance calories.
2. Eat approximately that amount consistently.
3. Track body weight under reasonably consistent conditions.
4. Look at the trend over several weeks rather than individual daily readings.
5. Adjust your estimate if the trend clearly moves up or down.

Daily weight can fluctuate because of water, sodium, carbohydrate intake, digestion and other factors.

For that reason, a single weigh-in tells you very little about whether your calorie estimate is correct.

How many calories should you eat to gain weight?

Weight gain generally requires an average calorie surplus.

If your maintenance intake is approximately 2,400 calories, consuming more than that on average can produce weight gain over time.

The size of the surplus influences how quickly body weight changes.

People trying to gain muscle do not necessarily need an extremely large surplus. Strength training, sufficient protein and an appropriate overall diet are also important.

If your goal is muscle growth, calorie intake should therefore be considered alongside your protein intake and training.

Read How Much Protein Do You Need to Build Muscle? for a more detailed look at protein requirements.

Is 1,200 calories per day enough?

A 1,200-calorie diet is sometimes discussed as a generic weight-loss target, but it is not appropriate for everyone.

For many adults, particularly larger or more active people, 1,200 calories may represent a very large deficit.

A fixed low-calorie number ignores differences in:

• body size
• age
• sex
• activity
• training
• health
• nutritional requirements

Instead of choosing a low calorie target simply because it is common online, estimate your own energy needs first. (NIDDK)

Very low calorie intakes can make it difficult to meet nutritional needs and should not be treated as a universal strategy.

Is 1,500 calories per day enough?

It depends on the person.

For someone whose maintenance needs are relatively low, 1,500 calories could represent a moderate deficit.

For someone who maintains their weight at 2,800 calories, the same intake would create a much larger deficit.

The number itself therefore tells you less than the difference between that intake and your actual energy expenditure.

Is 2,000 calories per day enough?

For some adults, 2,000 calories may be close to maintenance.

For others it may produce weight loss, while for someone with lower energy expenditure it could exceed maintenance needs.

The familiar 2,000-calorie figure is useful as a general reference point, but it is not a personalized recommendation.

Is 2,500 calories per day too much?

Again, it depends on energy expenditure.

Around 2,500 calories is used by the NHS as a general daily reference for an average man.

A highly active person may need more.

A smaller or less active person may need less.

Whether 2,500 calories causes weight gain depends primarily on how it compares with that person's energy expenditure over time.

Calories and activity level

Activity is one of the hardest variables to estimate accurately.

Two people who both describe themselves as "moderately active" may have very different lifestyles.

One might sit at a desk for most of the day and exercise four times per week.

Another might work on their feet, walk several kilometers every day and also train four times per week.

Their formal exercise schedules look similar, but total daily energy expenditure can be quite different.

This is why an activity multiplier should be treated as a starting estimate.

Why calorie calculators are estimates

No simple calculator can know exactly how many calories you burn.

Equations estimate energy expenditure from population data.

Individual differences can arise from:

• body composition
• spontaneous movement
• exercise
• occupation
• genetics
• measurement error
• changes in body weight
• changes in activity
• metabolic adaptation

Research comparing resting metabolic rate equations also shows that prediction errors occur at the individual level even when an equation performs reasonably well across a group. (RMR validation study)

Use a calculated target as a starting point, then refine it using your own weight and intake trends.

Why calorie needs change during weight loss

Your calorie requirement is not necessarily fixed forever.

As body weight decreases, maintaining the smaller body generally requires less energy.

Activity may also change, and the body can adapt to changes in energy intake and body weight.

This is one reason the simple idea that a fixed calorie deficit will produce exactly the same rate of weight loss indefinitely is inaccurate.

The NIH Body Weight Planner uses a dynamic mathematical model to account for changes in energy expenditure and body weight over time.

For practical tracking, this means your calorie target may occasionally need to be recalculated as your weight, activity or goals change.

Do you have to count calories?

No.

Calorie counting is one method of managing energy intake, not a requirement for a healthy diet.

Some people find tracking useful because it makes portions and eating patterns easier to understand.

Others prefer approaches based on:

• consistent meal structure
• portion awareness
• minimally processed foods
• vegetables and fruit
• protein-rich foods
• high-fiber foods
• regular meal timing

The underlying energy balance still matters for body-weight change even if you never manually count a calorie.

Calories are not the whole story

Two diets containing the same number of calories can differ substantially in nutritional quality.

Calories tell you how much energy food provides. They do not tell you everything about:

• protein
• fiber
• vitamins
• minerals
• essential fats
• food quality
• satiety

For example, someone can technically reach a calorie target while eating a diet that provides too little protein or fiber.

A useful nutrition plan therefore considers both energy intake and food quality.

If you are also trying to set your protein target, read How Much Protein Do You Need Per Day? or use the Mealisa Protein Calculator.

How to make your calorie estimate more accurate

You can improve an initial estimate with real-world data.

1. Start with a calculated estimate

Use your age, sex, height, weight and realistic activity level.

2. Track consistently

If you track food, consistency matters more than trying to achieve perfect precision.

Remember to include foods and drinks that are easy to overlook, such as:

• cooking oils
• sauces
• dressings
• snacks
• caloric drinks
• alcohol

3. Watch the trend

Body weight naturally fluctuates.

Compare averages or longer-term trends instead of reacting to one day's measurement.

4. Reassess

If your weight trend does not match your goal after a reasonable period, reassess your calorie estimate, food tracking and activity.

5. Recalculate after meaningful changes

Your needs may change after substantial weight loss or gain, or when your activity level changes.

Example: estimating calories for one person

Consider a 35-year-old man who weighs 75 kg and is 180 cm tall.

Using the Mifflin-St Jeor equation:

RMR = 10 × 75 + 6.25 × 180 − 5 × 35 + 5

That gives an estimated resting energy expenditure of approximately:

1,705 calories per day

If he is moderately active and uses an illustrative multiplier of 1.55:

1,705 × 1.55 ≈ 2,643 calories per day

That would make roughly 2,640 calories an initial maintenance estimate.

It is not a guarantee that exactly 2,640 calories will maintain his weight.

His real-world weight trend would help refine the estimate.

Frequently asked questions

How many calories should I eat a day?

There is no universal number. Your calorie needs depend on age, sex, height, weight and activity. General guidance often uses approximately 2,000 calories for women and 2,500 for men, but personalized needs can differ considerably.

How do I know my maintenance calories?

Estimate your total daily energy expenditure using your resting energy needs and activity level, then compare the estimate with your body-weight trend over several weeks.

Should I eat below my BMR or RMR?

RMR represents estimated energy use at rest, not a recommended calorie intake. Your total daily expenditure is higher because normal life includes movement, digestion and physical activity. A calorie target should therefore be based on the broader context rather than treating RMR as a minimum or a diet target by itself.

How many calories do I burn per day?

Your total daily expenditure includes resting metabolism, physical activity and the energy used to process food. It varies substantially between individuals and from day to day.

Does exercise increase how many calories I can eat?

Physical activity contributes to energy expenditure, so higher activity can increase calorie needs. However, exercise calorie estimates from watches, machines and apps are not perfectly accurate.

Why am I not losing weight at my calculated calorie target?

Possible reasons include an inaccurate maintenance estimate, changes in activity, incomplete food tracking, normal water-weight fluctuations or simply not having enough time to see the underlying trend.

If the expected trend does not appear over time, reassess the estimate rather than assuming a calculator result is exact.

Bottom line

The number of calories you should eat per day depends on your individual energy expenditure and your goal.

General population figures such as 2,000 calories for women and 2,500 for men can provide context, but they are not personalized prescriptions.

A better starting point is to estimate your resting energy expenditure, adjust for activity and then use your real-world weight trend to refine the result.

If your goal is weight loss, create a reasonable calorie deficit rather than automatically choosing the lowest intake possible.

If your goal is maintenance, start near estimated TDEE and adjust based on your weight trend.

And remember that calories are only one part of nutrition. Protein, fiber, micronutrients, food quality and dietary sustainability matter too.

Evidence note: This guide uses general energy-balance guidance from the NHS and NIDDK/NIH and the Mifflin-St Jeor resting-energy equation published in the American Journal of Clinical Nutrition. Predictive equations provide estimates, not direct measurements of an individual's metabolism.

This article provides general nutrition information for adults and is not individualized medical or dietetic advice. Calorie needs may require professional assessment during pregnancy or breastfeeding, for people under 18, for people with eating disorders or certain medical conditions, or when medically supervised nutrition therapy is required.

Continue exploring nutrition

• How Much Protein Do You Need Per Day?
• How Much Protein Do You Need per kg of Body Weight?
• High-Protein Foods: 30 Foods to Help You Eat More Protein
• High-Protein Foods for Weight Loss

Sources

Evidence and authoritative guidance used for the nutrition and health information in this article:

• Frankenfield et al. — Resting metabolic rate prediction equations: systematic review
• Mifflin-St Jeor and other resting metabolic rate equations: validation study
• NIDDK — Body Weight Planner