To calculate your maintenance calories, work out your basal metabolic rate with the Mifflin-St Jeor equation, then multiply it by an activity factor that matches how much you actually move in a normal week. Eat at that number for two to four weeks and your weight should hold steady, which makes it the honest starting point for any weight loss or weight gain plan.
Most people get the arithmetic right and the input wrong. They pick a gym membership as activity, forget the cooking oil, then wonder why the scale refuses to move for a month. The number itself takes two minutes. Making it true takes three weeks.
Table of Contents
- What You Need
- Step-by-Step: How to Calculate Your Maintenance Calories
- 1. Record Your Current Body Details
- 2. Estimate Your Daily Activity Level
- 3. Calculate Your Initial Estimate
- 4. Log Your Typical Food Intake
- 5. Check the Estimate Against Your Weight
- 6. Use Your Maintenance Number Responsibly
- Common Mistakes
- Frequently Asked Questions
- Is 1,200 calories enough for maintenance?
- Is 2,000 calories a day maintenance?
- Is the 4-4-9 rule accurate?
- How accurate are maintenance calorie calculators?
- How long does it take to find my real maintenance calories?
- Conclusion
What You Need
You need five personal details and one honest habit of record-keeping. Both matter more than the formula you choose.
- Your age in years. It appears in every equation, and expenditure drifts down slowly as you age.
- Your sex. The equations use a different constant for men and women.
- Your height. Measure once, in the morning, against a flat wall rather than estimating.
- Your current weight. Use a weekly average, not whatever the scale said on Tuesday after a salty dinner.
- Your real activity level. An honest description of a normal week, not your goal week.
- A tracking app or food database, plus three to seven days of records describing how you normally eat, not how you eat on a good day.
Consistency beats precision here. A height measured to the nearest centimetre changes the result by about six calories, while an activity factor chosen a whole level too high changes it by several hundred.
Home measurements and online calculators are useful estimates. They are not medical assessments, and anyone with a medical condition, a history of disordered eating, or an active eating disorder should talk to a registered dietitian before tracking intake at all.
Step-by-Step: How to Calculate Your Maintenance Calories
1. Record Your Current Body Details
Write down age, sex, height and weight before you open a calculator. Height and weight are the two inputs with the largest effect, and both are the two people most often guess at.
Measure height against a wall in the morning without shoes. For weight, weigh daily for a week under similar conditions and average the seven readings. Day-to-day swings of one to two kilograms are normal and come from water, sodium and gut contents, so a single reading is a poor input.
Use numbers from the last two weeks, not from a weigh-in you did last spring. Weight changes slowly, and an old input quietly shifts every number downstream.
2. Estimate Your Daily Activity Level
This is where most estimates go wrong. The multipliers are averages published in nutrition textbooks, so they describe populations rather than individuals. Pick the row that describes an ordinary week, including the weeks you skip the gym.
| Multiplier | Activity level | What a normal week looks like |
|---|---|---|
| 1.2 | Sedentary | Desk work, little deliberate exercise, roughly under 5,000 steps a day |
| 1.375 | Lightly active | Desk work plus walking or light training 1-3 days a week |
| 1.55 | Moderately active | Standing job, or training 3-5 days a week, around 7,500-10,000 steps |
| 1.725 | Very active | Training 6-7 days, or physical work such as delivery, farming or shifts on your feet |
| 1.9 | Extra active | Two-a-day training, competitive endurance sport, or heavy manual labour |
A reasonable approach when the categories blur is to pick the lower row, eat there for two weeks, then adjust. Advice repeated across r/loseit and r/CICO follows the same shape: treat the calculator as a starting point and let the scale over weeks correct it.
3. Calculate Your Initial Estimate
The Mifflin-St Jeor equation is the standard choice because it was derived from measured data rather than guessed at. In full, with the sex constants most printed versions leave out:
Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
Other equations exist and they do not agree with each other. Here is how the three main ones compare.
| Equation | What it needs | Accuracy verdict | Best use |
|---|---|---|---|
| Mifflin-St Jeor | Weight, height, age, sex | Best all-round accuracy across body types | Your default choice |
| Revised Harris-Benedict | Weight, height, age, sex | Tends to overestimate, especially at higher body fat | A quick cross-check, treated with caution |
| Cunningham | Weight expressed as lean mass | Very accurate but only if you know lean mass | People who already track body composition |
Worked example, showing every step. A 34-year-old woman, 165 cm, 68 kg, moderately active:
BMR = (10 × 68) + (6.25 × 165) − (5 × 34) − 161 = 680 + 1031 − 170 − 161 = 1,380
Maintenance = 1,380 × 1.55 = 2,140 calories a day
Treat 2,140 as a first guess, not a verdict. Any equation produces a range, not a fact, and a few hundred calories either way is well inside normal error.
4. Log Your Typical Food Intake
Now you do the part that makes the estimate real. Track everything for three to seven days that include a weekend, because a Saturday is often very different from a Tuesday.
Count every calorie that passes through: drinks, sauces, dressings, cooking oil, butter, nut butter, the handful of cheese you ate standing at the fridge. Oil is the classic one, and a tablespoon carries roughly 120 calories that people rarely record.
A simple day might run to 420 at breakfast, 610 at lunch, 690 at dinner and 180 of drinks and snacks, giving 1,900. That total, compared with an estimated 2,140, tells you something useful before you change a single thing about how you eat.
Portion estimates are the weak point of any paper diary. Weighing the food for three days fixes most of it.
5. Check the Estimate Against Your Weight
Keep weighing in every morning and keep eating at the same number for two to four weeks. Compare the average of week one with the average of the last week, not single readings.
Three outcomes are normal:
- Weight holds steady. You have found your maintenance calories. Most people need two to four weeks to see a clear trend.
- Weight falls gradually. You were eating below maintenance. Add 100 to 200 calories, or keep the lower number if losing weight was the goal.
- Weight climbs gradually. The estimate was too high, or your logging missed something. Subtract 100 to 200 calories and repeat.
Scale readings swing by a kilo or more overnight because of sodium, carbohydrate intake, bowel movements, menstrual cycles and training. Two days of a higher number mean nothing; a steady trend across three weeks means a lot.
Small changes can look like nothing at all on the scale. That is not a myth being repeated here, it is a real effect: non-exercise activity thermogenesis, or NEAT, tends to fall when you deliberately eat less, and people unconsciously move more when they eat more. A 150-calorie adjustment often shows up as a plateau that breaks a week later, or not at all.
6. Use Your Maintenance Number Responsibly
The number is a baseline for three different jobs. Holding weight means eating at it. Gradual loss usually means 10 to 15 percent below it. Gradual gain means 5 to 10 percent above it, along with enough protein and resistance training to build lean mass rather than fat.
Using the example above: 2,140 for stability, roughly 1,820 to 1,920 for a moderate deficit, and roughly 2,240 to 2,350 for a lean gain. Aggressive cuts are not necessary and rarely hold.
After a run of dieting, raise intake gradually rather than jumping straight back to a high number. Long deficits bring metabolic adaptation, where expenditure settles lower to match the reduced intake, and that is when a maintenance number that was once accurate stops being accurate.
If you have a medical condition, take medication that affects appetite or metabolism, are pregnant or breastfeeding, or have a history of disordered eating, get individual advice from a registered dietitian instead of running the numbers yourself.
Common Mistakes
Most wrong maintenance numbers come from one of four errors, and each has an easy correction.
- Choosing activity from intent instead of routine. A gym membership you pay for but visit twice a month is not moderate activity. Correction: describe last month’s actual week, not the one you are planning.
- Ignoring drinks, sauces and cooking fats. Liquid calories do not trigger the same fullness response as solid food. Correction: weigh portion sizes for three days and log every drop of oil.
- Checking the scale too often. Daily readings bounce; they do not describe progress. Correction: weigh daily, then only ever look at the weekly average.
- Treating the calculator result as a diagnosis. An equation cannot see your body composition, your sleep or your stress. Correction: treat it as the first number in a two-to-four-week experiment.
The 4-4-9 rule, where you multiply your weight in pounds by nine, is not accurate. It assumes a fixed 30 percent share for activity in every person, which does not hold for a desk worker or a bricklayer. The old weight-times-ten shortcut has the same problem. Both return numbers that can be hundreds of calories off in either direction.
Three habits make the whole process work: log the same days each week, change one number at a time, and give every adjustment a full two weeks before judging it. On forums like r/workout, the most useful advice is exactly this — pick one number, eat it for a month, then adjust.
Use maintenance calories as your reference point, not a rule carved in stone. If you have been eating far below that number for months, add 100 to 200 calories at a time and expect a short period of rising scale readings before things settle.
Frequently Asked Questions
Is 1,200 calories enough for maintenance?
For most adults, no. 1,200 calories sits at or below maintenance for a small woman and well below it for anyone larger, which means it works as a weight loss target rather than a maintenance one. Rough maintenance ranges run from about 1,200 to 1,600 for a small sedentary woman up to about 2,200 to 3,000 for a large active man. Check your own estimate with the Mifflin-St Jeor method before assuming any generic number applies to you.
Is 2,000 calories a day maintenance?
For plenty of women in their thirties and forties, yes, and it is close for a moderately active man of average build. It is too low for a large or very active adult and far too high for a small sedentary one, which is why a single number cannot answer the question. Run your own estimate, then confirm it by eating at that level for two to four weeks and watching the weekly average weight.
Is the 4-4-9 rule accurate?
No. The rule assumes everyone spends about 30 percent of their calories on activity, from a sedentary desk worker to a manual labourer. Real activity share varies far more than that, so 4-4-9 can miss by several hundred calories in either direction. It also ignores age, sex and height entirely. The Mifflin-St Jeor equation followed by an honest activity factor is a better starting point, and tracking settles the rest.
How accurate are maintenance calorie calculators?
Reasonably good as a starting point, and they usually land slightly high. The error comes from the activity factor, which asks you to describe yourself and defaults generously, and from equations that ignore body composition. The most useful pattern is to treat the result as a hypothesis, eat at that number for two to four weeks, then adjust by 100 to 200 calories based on the direction of your weekly average weight.
How long does it take to find my real maintenance calories?
Two to four weeks of consistent data is the practical minimum, and longer if your weight has been moving recently. Day-to-day readings are meaningless on their own because of water, sodium and cycle changes, so compare weekly averages rather than single numbers. If you have spent months eating well below maintenance, expect the first couple of weeks after raising intake to be noisy before a new stable weight appears.
Conclusion
Start with the record: a week of honest food logging, current weight from a weekly average, and one Mifflin-St Jeor calculation multiplied by an honest activity factor. Then eat that number for two to four weeks and let the weekly average weight tell you which direction to move.
That is how to calculate your maintenance calories well enough to act on. Treat the number as a starting point that moves as your life, training and body change, and get individual guidance from a registered dietitian when a medical condition or your eating history makes self-tracking the wrong tool.
