How Many Calories to Maintain Weight? Find Your Number

How many calories to maintain weight depends on you. Guide figures put it at about 2,000 kcal a day for women and 2,500 kcal for men. That’s the NHS guide, and an equation that uses your age, height, weight and activity gets closer. For a 35-year-old woman at 165 cm and 70 kg it gives about 2,270 kcal. Either figure is an estimate. Weigh-ins correct it.

How do I work out how many calories to maintain weight?

Maintenance calories are what you eat on days when your weight doesn’t change. That equals your total daily energy expenditure, or TDEE, the energy your body uses in a day. For a weight-stable adult, the 2023 NASEM report sets the estimated energy requirement equal to total energy expenditure, so one equation gives you both. Here’s how to calculate your TDEE by hand if you want every step.

The committee built it from 8,600 doubly labeled water measurements across all ages. In those studies people drink water tagged with two isotopes, and researchers track their real energy use over 7 to 14 days. You need age in years, height in cm, weight in kg and an activity level. The adult coefficients are below.

Activity level	Women (kcal a day)	Men (kcal a day)
Inactive	584.90 − 7.01 × age + 5.72 × height + 11.71 × weight	753.07 − 10.83 × age + 6.50 × height + 14.10 × weight
Low active	575.77 − 7.01 × age + 6.60 × height + 12.14 × weight	581.47 − 10.83 × age + 8.30 × height + 14.94 × weight
Active	710.25 − 7.01 × age + 6.54 × height + 12.34 × weight	1,004.82 − 10.83 × age + 6.52 × height + 15.91 × weight
Very active	511.83 − 7.01 × age + 9.07 × height + 12.56 × weight	−517.88 − 10.83 × age + 15.61 × height + 19.11 × weight

I ran my example woman through the low active row. She is 35, 165 cm and 70 kg. The sum is 575.77 − (7.01 × 35) + (6.60 × 165) + (12.14 × 70), which is 575.77 − 245.35 + 1,089.00 + 849.80 = 2,269 kcal. In kilojoules that is about 9,494.

Pick your row, put in your numbers and write the result down to the nearest 10 kcal. You’ll test it further down. For targets above or below it, start with how many calories you need per day.

What do inactive, low active and active mean?

Activity is the hardest input to pick, because the words sound like gym talk. NASEM defines the levels by the movement added to daily living, and the report’s examples put numbers on them. Inactive is daily living only. Low active adds 60 to 80 minutes of walking at 3 to 4 mph. Active adds 30 to 50 minutes of walking plus about 85 minutes of cycling and tennis. Very active adds more than 2 hours of vigorous exercise.

The choice moves the answer a lot. Here is the same woman, with the same height and weight, in all four rows.

Activity level	Maintenance calories (kcal)	Maintenance calories (kJ)
Inactive	2,103	8,799
Low active	2,269	9,494
Active	2,408	10,074
Very active	2,642	11,055

One step up adds 139 to 234 kcal. I would put a desk worker who trains three times a week in low active. A level describes your average day over a week or two, not the day you train. When two rows fit, I take the lower one, and the weigh-in check below shows within a few weeks if it was too low.

To skip the arithmetic, use the calorie calculator. It runs the same NASEM 2023 equations and keeps a safe minimum under every goal.

What are my maintenance calories in the UK?

Use the same equation. Only the starting units differ. The NHS says an average man needs 2,500 kcal a day and an average woman 2,000 kcal. Both depend on age, weight, height and how much exercise you do.

Convert first. One stone is 6.35 kg, so 11 stone is 69.9 kg. Height goes from feet and inches to centimeters, and 5 ft 5 in is 165 cm. The NHS notes that calorie information is often given in kcal and may also be given in kJ, so use the kcal figure. To compare with the kilojoule figure on a pack, multiply kcal by 4.184.

How do I check my number against real life?

Eat your estimate for three to four weeks, weigh yourself most mornings and compare the first and last week’s average. NASEM calls this step two of its method: monitor body weight over time and adjust intake. Maintenance is a band.

The standard error is 241 kcal for women and 342 kcal for men. For my example woman, about two thirds of women like her need between 2,028 and 2,510 kcal. Her true number could sit anywhere in that band, which makes the equation a starting point.

To read a weight change, I turn it into calories. A kilogram of body weight is worth roughly 7,700 kcal, or 3,500 kcal per pound, the rule of thumb Kevin Hall examined in 2008. Say you averaged 2,300 kcal a day for 28 days and your weekly average weight rose 0.6 kg. That is 0.6 × 7,700 = 4,620 kcal over 28 days, or about 165 kcal a day. Your maintenance is near 2,300 − 165 = 2,135 kcal.

The rule has limits. Hall’s paper is about weight loss, the same ground as using your TDEE to lose weight. It found the rule fits people with more than 30 kg of body fat and overstates the deficit needed for leaner people. Treat 7,700 as a rough guide over a month.

Food logging adds its own error. The OPEN study compared 24-hour recalls with doubly labeled water in 484 adults aged 40 to 69. Men underreported energy intake by 12 to 14% and women by 16 to 20%. A diary filled in from memory can fake a low maintenance number. Weigh the foods you eat most often first. Step on the scale under the same conditions each day, for example after the toilet and before breakfast.

Why do maintenance calories change over time?

The inputs change. Weight is the easy one. In the low active rows of the NASEM equation, each extra kilogram adds 12.14 kcal for women and 14.94 kcal for men. Gain 5 kg and my example woman’s number rises by about 61 kcal. Age pulls the other way. Each year takes off 7.01 kcal for women and 10.83 kcal for men, so ten years is 70 kcal and 108 kcal. At 45 her number is 2,199 kcal.

Measured data shows a flatter picture. A 2021 Science analysis of doubly labeled water data found expenditure per kilogram of fat-free mass stable from 20 to 60 years. It declined afterwards. Total use can still fall when lean mass falls. So I don’t cut my number by a fixed amount each birthday. I recheck it against the scale.

Pregnancy, breastfeeding and anyone under 18 fall outside this equation, which was built for adults, and a midwife or doctor sets those needs. If your weight has dropped without a reason, see your doctor before you change how much you eat. The NHS asks you to speak to a GP if you have lost weight suddenly or without changing your routine.

What do I do with the number?

Hold the estimate for three weeks. If your weight rose, take the daily gap from the arithmetic above off the number. If it fell, add the gap. Then hold the new number for another three weeks. If you want the scale to go up on purpose, see how big a calorie surplus to run. After two rounds the number rests on your own weigh-ins instead of an average, and it holds until your weight, job or training changes.

Calsa smooths daily weigh-ins into one weight trend, so the three-week check reads as a line, and it offers a maintenance goal once you reach your weight.