How many calories should I eat a day?

What your number is made of

There’s no single right number for everyone. The calories you need each day come down to two things: what your body burns at rest, and how much you move on top of that.

• Resting energy keeps you breathing, warm and thinking. For most adults it’s the biggest share of the day, and it depends mainly on your size, age and sex.
• Activity covers everything else: walking, working, training, even fidgeting.

Add the two together and you get your maintenance calories, the amount that keeps your weight about where it is. You may also see it called TDEE, short for total daily energy expenditure. It’s the same idea.

Work it out in two steps

The Mifflin–St Jeor equation is one of the most widely used ways to estimate resting energy. Use your weight in kilograms, your height in centimetres and your age in years:

• Women: 10 × weight + 6.25 × height − 5 × age − 161
• Men: 10 × weight + 6.25 × height − 5 × age + 5

Then multiply the result by your activity level:

• Mostly sitting: × 1.2
• Lightly active (light exercise 1–3 days a week): × 1.375
• Moderately active (exercise 3–5 days a week): × 1.55
• Very active (hard exercise most days): × 1.725

For example, take a 35-year-old woman who is 165 cm (5 ft 5 in) tall, weighs 68 kg (150 lb) and goes for a run twice a week. Her resting energy is about 1,375 calories. Multiplied by 1.375 for light activity, her maintenance comes to about 1,890 calories a day.

Be honest about activity. Most people overestimate it, and a desk job with a couple of workouts a week is usually “lightly active”, not “very active”.

Adjust for your goal

• To maintain your weight: eat around your maintenance number.
• To lose weight: eat a little less. A modest gap of about 10–20% below maintenance is far easier to live with than a crash diet. For the example above, 10% less is about 1,700 calories.
• To gain weight: eat a little more, with a similar modest step up.

Bigger cuts aren’t better. Very low intakes are hard to keep up and make it harder to get enough protein and nutrients. Our guide to calorie deficits shows how to choose a gap you can stick with.

Check it against real life

Any formula is an estimate. Two people of the same age, height and weight can burn noticeably different amounts. Treat your number as a starting point, then let your own results fine-tune it:

1. Eat around your target for two to three weeks, logging your meals as you go.
2. Weigh yourself a few times a week at the same time of day, and watch the trend rather than single days.
3. Adjust by 100–200 calories if your weight isn’t moving the way you expect, then check again.

These calculations are meant for healthy adults. If you’re pregnant or breastfeeding, under 18 or managing a medical condition, ask a doctor or dietitian for a target that fits you.

Let Meali do the maths

Skip the calculator. Add your age, height, weight and activity in Meali’s Nutrition goals, choose whether to maintain, lose or gain, and tap Calculate for me. Meali works out your daily calories plus protein, carb and fat targets with the same formula, and keeps them up to date when you log a new weight.

Already have targets from a coach or dietitian? Choose Set myself and enter them. Then write, snap or say what you eat, and your daily summary shows how each day compares. Targets are always optional, so you can keep a simple journal without them.