How Many Calories Should You Eat a Day? Find Your Number

In brief: how many calories you should eat a day depends on your age, sex, body size and activity. US guidelines estimate about 1,600–2,400 calories a day for adult women and 2,000–3,000 for adult men. The NHS uses simpler averages of 2,000 and 2,500. For a personal figure, estimate your resting burn, then multiply it by your activity level.

How Many Calories Should I Eat a Day by Age?

The most detailed official estimates come from the Dietary Guidelines for Americans. They give a calorie figure for each age group at three activity levels. "Sedentary" means only the movement of everyday life. "Moderately active" adds the equivalent of a daily brisk walk of 1.5 to 3 miles (2.4 to 4.8 km). "Active" means more than 3 miles a day on top of daily life.

Age	Women: sedentary	Women: moderately active	Women: active	Men: sedentary	Men: moderately active	Men: active
19–20	2,000	2,200	2,400	2,600	2,800	3,000
21–25	2,000	2,200	2,400	2,400	2,800	3,000
26–30	1,800	2,000	2,400	2,400	2,600	3,000
31–40	1,800	2,000	2,200	2,400	2,600	2,800–3,000
41–50	1,800	2,000	2,200	2,200	2,400–2,600	2,800
51–60	1,600	1,800	2,200	2,200	2,400	2,600–2,800
61–75	1,600	1,800	2,000	2,000	2,200–2,400	2,600
76+	1,600	1,800	2,000	2,000	2,200	2,400

Where a cell shows a range, the guidelines give different figures for the five-year bands inside that age group. The estimates are calculated for people of median height at a healthy weight. That's why they're a guide rather than a prescription. A tall, heavy person burns more than the table suggests, and a small, light person burns less.

Two patterns stand out. Needs fall slowly with age. And activity matters as much as sex. An active woman in her twenties needs about as much as a sedentary man of the same age.

Why Averages Only Get You Part of the Way

The NHS's rounded figures of 2,000 calories for women and 2,500 for men are useful for reading food labels. But your daily calorie needs can sit hundreds of calories either side of them. Three things drive the difference:

• Body size. A larger body needs more energy to run, even at rest.
• Age. Resting energy use declines gradually through adulthood.
• Movement. Exercise and everyday activity add to your resting burn. Moving from the sedentary multiplier (1.2) to the very active one (1.725) adds about 735 calories a day for someone with a BMR of 1,400.

How to Work Out Your Own Daily Calorie Needs

Calculating your own number takes two steps.

Step 1: Estimate your basal metabolic rate (BMR)

Your BMR is the energy your body uses at complete rest: breathing, circulation, keeping warm. The most widely used formula is the Mifflin-St Jeor equation, published in 1990. It was developed from measurements of 498 healthy adults aged 19 to 78.

• Women: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
• Men: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5

A 2005 systematic review compared it with the other common equations. Mifflin-St Jeor came out as the most reliable: it estimated resting energy use to within 10% of the measured value in more people than any other formula. Even so, no equation is exact for every individual.

Step 2: Multiply by your activity level

Your total daily energy expenditure (TDEE) is your BMR plus the energy you use moving. It's estimated by multiplying BMR by an activity factor. These multipliers are a widely used convention, not a measurement of you:

Activity level	Typical week	Multiplier
Sedentary	Desk job, little exercise	1.2
Lightly active	Exercise 1–3 days	1.375
Moderately active	Exercise 3–5 days	1.55
Very active	Hard exercise 6–7 days	1.725
Extra active	Physical job plus training	1.9

Your TDEE is your maintenance calories: eat about this much and your weight should stay roughly stable. If you're between two levels, pick the lower one and adjust later. The TDEE calculator does both steps for you in metric or imperial units.

A Worked Example

Take a 35-year-old woman who is 165 cm (5 ft 5 in) tall, weighs 70 kg (154 lb) and exercises three to five days a week.

• BMR = (10 × 70) + (6.25 × 165) − (5 × 35) − 161 = 700 + 1,031 − 175 − 161 = about 1,395 calories
• TDEE = 1,395 × 1.55 = about 2,160 calories a day

The guidelines table gives 2,000 calories for a moderately active woman aged 31–35. Her personal estimate is a little higher because she is somewhat heavier than the reference body the table assumes. Both figures are reasonable starting points. Her scale over the next few weeks will tell her which is closer.

How Many Calories Should I Eat to Lose Weight?

To lose weight, you eat less than your maintenance calories. The gap is called a calorie deficit. The NHS suggests aiming to lose 0.5 to 1 kg (1 to 2 lb) a week. A deficit of roughly 250 to 550 calories a day puts most people at the slower, more sustainable end of that range. For the woman in the example, that means about 1,600 to 1,900 calories a day.

How big your deficit should be, and why weight loss slows over time, is covered in our guide to the calorie deficit you need to lose weight. To turn a calorie target into protein, carbs and fat, see how to calculate macros.

Limits and When to Get Advice

Every number here is an estimate. Prediction equations were built on groups of people, and your real burn can differ from the formula's answer. Treat your first figure as a hypothesis. Eat at it for two to three weeks, weigh yourself under the same conditions each time, and adjust by 100 to 200 calories a day if your weight moves differently than you expected.

These methods are for healthy adults. They don't apply during pregnancy or breastfeeding, to children and teenagers, or to anyone with a medical condition that affects weight or metabolism. In those cases, ask a doctor or registered dietitian for a figure that fits you.

Frequently Asked Questions

Is 2,000 calories a day right for everyone?

No. 2,000 is a round figure used on food labels and as an average for women. Official US estimates for adults run from about 1,600 to 3,000 calories a day. Where you fall depends on your age, sex, size and activity. A small, inactive older adult may need well under 2,000, while a young, active man may need far more.

Do I need fewer calories as I get older?

Usually, yes. In the Dietary Guidelines estimates, a sedentary woman's needs drop from 2,000 calories a day in her early twenties to 1,600 from her fifties onward. A sedentary man's fall from 2,600 at 19–20 to 2,000 from his sixties. Staying active keeps your activity multiplier, and your needs, higher.

What is the difference between BMR and TDEE?

BMR is the energy you burn at complete rest, just to keep your body running. TDEE is your total daily burn: BMR plus everything you spend on movement, exercise and digesting food. TDEE is the number to plan your eating around. BMR is only the first step in calculating it.

Should I eat back the calories I burn exercising?

If you set your target from a TDEE that already includes your exercise, don't add exercise calories on top. That would count them twice. Exercise burn from a fitness tracker is an estimate too. If you use one, be cautious about eating back everything it reports, and let your weight trend guide you.

To get a personal estimate from your own height, weight, age and activity, use the TDEE calculator.