Most adults need roughly 1,400 to 2,400 kcal a day (women) and 1,900 to 3,100 kcal a day (men) to maintain their weight. The exact number depends on body size, age, sex and activity. Needs fall by about 50 kcal of resting energy per decade of age, while daily movement can add hundreds of calories.
Key takeaways
- Calorie needs = resting energy (BMR) multiplied by an activity factor from 1.2 to 1.9.
- Men usually need more than women of the same size because the formula adds about 166 kcal to the male BMR.
- Each extra decade of age lowers resting energy by about 50 kcal a day in the Mifflin-St Jeor equation.
- Activity is the biggest lever: going from sedentary to moderately active adds roughly 400–650 kcal a day.
- Any table is an estimate; your weight trend over several weeks tells you your real number.
How are daily calorie needs worked out?
Your daily calorie need, often called maintenance calories or total daily energy expenditure (TDEE), is the amount of energy that keeps your weight stable. It has two main parts: the energy your body uses at rest to keep you alive (basal metabolic rate, BMR) and the extra energy you use moving around, working and exercising.
The most widely used way to estimate BMR is the Mifflin-St Jeor equation:
- Women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
- Men: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
BMR is then multiplied by an activity factor: 1.2 for sedentary, 1.375 for lightly active, 1.55 for moderately active, 1.725 for very active and 1.9 for extremely active people. The result is your estimated maintenance number. Our article on TDEE explained goes into each part in more detail. The US National Academies use a similar idea when they set Estimated Energy Requirements at several levels of physical activity.
Mifflin-St Jeor equation × activity factor. Capped at the usual minimum (1,200 kcal women / 1,500 kcal men); going lower needs medical supervision. Estimates only.
How many calories do women need by age and activity?
The table below uses the formula for a woman who is 165 cm (5 ft 5 in) tall and weighs 65 kg (143 lb). Numbers are rounded to the nearest 10 kcal.
| Age | Sedentary (×1.2) | Lightly active (×1.375) | Moderately active (×1.55) | Very active (×1.725) |
|---|---|---|---|---|
| 25 | 1,670 | 1,920 | 2,160 | 2,410 |
| 45 | 1,550 | 1,780 | 2,010 | 2,230 |
| 65 | 1,430 | 1,640 | 1,850 | 2,060 |
How many calories do men need by age and activity?
This table uses a man who is 178 cm (5 ft 10 in) tall and weighs 80 kg (176 lb).
| Age | Sedentary (×1.2) | Lightly active (×1.375) | Moderately active (×1.55) | Very active (×1.725) |
|---|---|---|---|---|
| 25 | 2,150 | 2,460 | 2,780 | 3,090 |
| 45 | 2,030 | 2,330 | 2,620 | 2,920 |
| 65 | 1,910 | 2,190 | 2,470 | 2,750 |
These are examples, not targets. A shorter, lighter person will need less than the table shows, and a taller, heavier person more. Use them to see how the pieces move, then calculate your own number.
Why do men usually need more calories than women?
Two reasons. First, the equation itself: for the same weight, height and age, the male formula adds 5 and the female formula subtracts 161, a gap of 166 kcal of resting energy. That difference reflects the fact that, on average, men carry more muscle and less fat at the same body weight, and muscle uses more energy at rest. Second, men are on average taller and heavier, and every extra kilogram adds 10 kcal and every extra centimetre adds 6.25 kcal to BMR.
In the example tables, the man is 13 cm taller and 15 kg heavier than the woman, so his needs are about 480 kcal higher when both are sedentary. A woman and a man of exactly the same size would differ by only about 200 kcal a day at a sedentary level.
How much do calorie needs drop with age?
In the Mifflin-St Jeor equation, each year of age subtracts 5 kcal from BMR, so each decade lowers resting energy by about 50 kcal a day. Multiplied by a moderate activity factor (1.55), that is roughly 80 kcal a day per decade. Between 25 and 65, the woman in the example needs about 310 kcal less a day at the same activity level.
Real life often widens that gap. Many people become less active as they get older and lose some muscle, which lowers both parts of the equation. The reverse is also true: staying active and doing some strength training helps keep needs higher. We cover this in more depth in losing weight after 40, and older adults may also want to read about protein needs later in life.
How do you choose the right activity level?
Picking the activity factor is where most estimates go wrong, usually because people choose a level that is too high. A rough guide:
| Level | Factor | What it looks like |
|---|---|---|
| Sedentary | 1.2 | Desk job, little walking, no planned exercise |
| Lightly active | 1.375 | Some walking every day or light exercise 1–3 days a week |
| Moderately active | 1.55 | Exercise 3–5 days a week or an on-your-feet job |
| Very active | 1.725 | Hard exercise 6–7 days a week or a physical job plus training |
| Extremely active | 1.9 | Heavy manual labour plus training, or athletes training twice a day |
For reference, the WHO recommends that adults get at least 150 minutes of moderate-intensity physical activity a week. Someone who meets that and otherwise sits most of the day is usually closer to lightly active than moderately active. Daily steps matter too; see how many steps a day help with weight loss. If you are unsure, pick the lower level and adjust after a few weeks.
What does this mean if you want to lose weight?
To lose weight, you eat a bit less than your maintenance number. A common starting point is a deficit of about 500 kcal a day, which by the rough rule that about 7,700 kcal equals 1 kg of body fat works out to roughly 0.5 kg (1 lb) a week. That rule is approximate, and weight loss slows as your body gets smaller. The CDC notes that people who lose about 0.5–1 kg (1–2 lb) a week are more likely to keep it off.
A worked example: the 45-year-old moderately active woman above needs about 2,010 kcal to maintain her weight. A 500 kcal deficit gives a target of about 1,510 kcal. A sedentary 65-year-old woman, though, maintains at about 1,430 kcal, so a full 500 kcal deficit would take her below 1,000 kcal. In that case a smaller deficit plus more movement is the safer route. As a general rule, do not go below 1,200 kcal a day for women or 1,500 kcal a day for men without medical supervision. Our guide on how many calories to eat to lose weight walks through the full process.
How accurate are these numbers?
Prediction equations estimate the average for people like you, and individuals can sit a few hundred calories above or below it. Body composition, genetics, health conditions, medication and how much you fidget all play a part. The NIH Body Weight Planner goes further by simulating how your needs change as your weight changes over time.
The most reliable check is your own data: eat close to your estimated number for two to four weeks, track your weight trend, and adjust by 100–200 kcal if it moves in a direction you did not expect. Sporty calculates a starting target from your age, sex, height, weight and activity level, and you can update the activity level and pace later as your routine changes.
Pregnancy, breastfeeding, being under 18 and medical conditions such as kidney disease all change energy needs. In those situations, ask a doctor or registered dietitian rather than relying on a general table.
Frequently asked questions
How many calories does an average woman need per day?
It depends on size, age and activity. For a 165 cm, 65 kg woman, the Mifflin-St Jeor equation gives about 1,550 kcal a day at 45 if sedentary and about 2,010 kcal if moderately active.
How many calories does an average man need per day?
For a 178 cm, 80 kg man aged 45, estimated needs are about 2,030 kcal a day if sedentary and about 2,620 kcal if moderately active. Taller, heavier or more active men need more.
Do you need fewer calories as you get older?
Yes, usually. The equation lowers resting energy by about 50 kcal per decade, and many people also move less and lose some muscle with age. Staying active and strength training helps keep needs up.
Which activity level should I choose?
Choose the level that matches a typical week, not your best week. If you are unsure, pick the lower option and adjust after two to four weeks based on your weight trend.
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This article is general information, not medical advice. If you have a health condition, are pregnant or under 18, talk to a doctor or registered dietitian before changing your diet.