Calorie Target Calculator
Maintenance calories from the Mifflin-St Jeor equation, then a daily target for every rate of loss or gain — and the calendar date each one would reach your goal weight. The dates are the honest part: the page also tells you why they are a best case.
You, and where you are going
Mifflin-St Jeor has one sex term, a constant of −161 or +5. It has no third option, so treat both figures as brackets if neither fits.
Whole years. Resting burn falls about 5 kcal a day for each year.
Centimetres, without shoes. 1.65 m is 165.
Weigh yourself at the same time of day. Week-to-week trend beats any single reading.
Only used for the projected dates. Set it equal to your current weight to plan on holding steady.
One step here is worth 150 to 300 kcal a day — more than the gap between two of the rates below. When in doubt, pick lower.
The headline target uses this one. Every rate is in the table either way.
Starts at today. Move it to plan from a date you know you will actually begin.
Maintenance is 2,201 kcal a day. Taking off 550 kcal a day gives 1,651. At that rate the goal arrives on April 9, 2026.
- Maintenance calories
- 2,201 kcal a day
- Resting burn (BMR)
- 1,420 kcal a day
- Change from maintenance
- -550 kcal a day
- Weight to change
- 7 kg to lose
- Time at this rate
- 14 weeks
- Maintenance at the goal weight
- 2,093 kcal a day
| Rate | Per week | Daily calories | Goal reached |
|---|---|---|---|
| Fast loss | −1 kg | 1,101 kcal — too low | February 19, 2026 |
| Steady loss | −0.5 kg | 1,651 kcal | April 9, 2026 |
| Slow loss | −0.3 kg | 1,926 kcal | July 16, 2026 |
| Maintain | — | 2,201 kcal | — |
| Slow gain | +0.3 kg | 2,476 kcal | — |
| Steady gain | +0.5 kg | 2,751 kcal | — |
| Fast gain | +1 kg | 3,301 kcal | — |
- The 7,700 kcal per kilo rule is a straight line through a curve. Maintenance falls as you get lighter — yours drops to 2,093 kcal at the goal weight — so a fixed intake becomes a smaller and smaller deficit. Real loss slows down and flattens; the dates above are a best case, not a schedule.
- Mifflin-St Jeor is accurate to within about 10% for most adults, which is ±220 kcal on a 2,201 kcal maintenance. Treat the first two weeks as measurement: if the scale trend does not match, adjust the intake rather than the equation.
- Moderately active multiplies resting burn by 1.55. These five buckets cover a range that really varies continuously, and self-reported activity runs high. If the trend disagrees, this is the input to doubt first.
This is general information, not medical advice
This page does arithmetic on a prediction equation and explains where the equation came from. It is general educational information. It is not medical advice, it is not a prescription, and it cannot see anything about you that an age, a height, a weight and a five-way activity dropdown do not capture — which is most of what matters.
Before you change what you eat in any sustained way, talk to a doctor or a registered dietitian. That goes double if you are pregnant or breastfeeding, under 18, an older adult, managing diabetes or thyroid disease, taking medication that affects appetite or metabolism, recovering from illness or surgery, or have any history of disordered eating. A calculator cannot tell when a number is the wrong thing to be looking at.
If counting calories makes you feel worse rather than better, stop. That reaction is information, and it is more important than anything on this page.
How the target is worked out
Three steps: predict resting burn, scale it for activity, then add or subtract the energy the chosen rate of weight change represents.
BMR = 10w + 6.25h − 5a + s • Maintenance = BMR × activity • Target = Maintenance ± (rate × E ÷ 7)- w, h, a
- Weight in kilograms, height in centimetres, age in years
- s
- The sex constant: +5 for men, −161 for women — the equation’s only sex term
- activity
- 1.2 sedentary, 1.375 light, 1.55 moderate, 1.725 very, 1.9 extra
- E
- Energy per unit of body mass: 7,700 kcal per kilogram, or 3,500 kcal per pound
The two energy constants are not conversions of one another — 3,500 kcal per pound works out to 7,716 per kilogram. They are two roundings of the same 1958 estimate of the energy density of adipose tissue, each rounded in the unit it was quoted in. This page keeps both, so the metric ladder runs 0.25 / 0.5 / 1 kg a week and the imperial ladder runs 0.5 / 1 / 2 lb a week, and the familiar “500 calories a day is a pound a week” comes out exact rather than nearly.
Imperial input is converted before it reaches the equation, using the exact definitions — 1 inch = 0.0254 m and 1 pound = 0.45359237 kg — rather than the rounded factors that circulate. Projected dates are counted in whole days from the start date, in UTC, and rounded up: you reach the goal on the day it finishes, not the day before.
A 30-year-old woman, 165 cm and 70 kg, aiming for 63 kg
Start with resting burn. Ten times the weight is 700. Six and a quarter times the height is 6.25 × 165 = 1,031.25. Five times the age is 150, subtracted. The female constant subtracts another 161. That is 700 + 1,031.25 − 150 − 161 = 1,420 kcal a day at complete rest.
Moderately active multiplies that by 1.55: 1,420.25 × 1.55 = 2,201 kcal a day to hold 70 kg steady. That is maintenance.
Half a kilogram a week is 0.5 × 7,700 = 3,850 kcal over seven days, which is 550 kcal a day. So the target is 2,201 − 550 = 1,651 kcal. Losing 7 kg at half a kilo a week takes 14 weeks — 98 days — so a plan starting on 30 July 2026 projects 5 November 2026.
Now the part most calculators leave out. Run the same equation at 63 kg and resting burn falls to 1,350 kcal, so maintenance falls to 2,093. The gap between 2,201 and 2,093 is 108 kcal a day, and it does not appear at the end — it shrinks the deficit continuously the whole way down. Eating 1,651 kcal at 63 kg is a 442 kcal deficit, not 550. The real curve arrives late.
Why 7,700 kcal per kilo overpredicts, and why plateaus are normal
The rule this page uses treats energy per unit of body mass as a constant, which makes weight loss a straight line: a fixed deficit removes a fixed amount of tissue every week, forever. Bodies are not linear. Maintenance is a function of mass, so as mass falls, maintenance falls with it — a lighter body has less tissue to keep running, less to carry around, and eats less food to digest. The deficit you set on day one is smaller on day sixty and smaller again on day two hundred, until it closes entirely and the scale stops. The curve flattens.
This is not a small correction. Kevin Hall’s 2008 analysis of the 3,500-calorie rule found that it overpredicts long-run loss by roughly a factor of two: a deficit the rule says will take off 25 kg over several years takes off closer to half that before the new maintenance catches up. The rule is a decent estimate for the first several weeks — which is why it survived — and a bad one for the first year.
What follows from that is the most useful thing on this page. A plateau is the expected behaviour of the system, not evidence that you have broken it, that your metabolism is damaged, or that you are secretly eating more than you think. It is what happens when a smaller body meets the intake that was set for a larger one. The response is to recalculate at your current weight and accept a smaller absolute deficit, or to accept the new weight — not to cut further and further in pursuit of a line that was never going to hold. The dates in the table above are best cases under a model that is known to be optimistic; treat them as an upper bound on speed, not a schedule you are failing to meet.
If you want a projection that models the deceleration properly, the US National Institute of Diabetes and Digestive and Kidney Diseases publishes the Body Weight Planner, built on the differential model Hall’s group developed. It is linked in the sources below. This page deliberately keeps the linear rule instead, because it is the vocabulary every clinician and food label already shares — and then tells you where it breaks.
This or the TDEE calculator?
They share one line of arithmetic and answer different questions. The TDEE calculator answers “how much do I burn?” — one number, estimated three ways, so you can see how much the choice of equation matters. Nothing about goals, no table, no dates. It is the right page when the maintenance figure itself is what you are after.
This page takes that number as step one and answers “what do I eat, and when does it get me there?” The rate ladder, the energy-per-mass conversion, the projected dates and the clinical floor all live here and nowhere else. Once you have a target, the macro calculator divides it into protein, carbohydrate and fat.
What the equation cannot see
Mifflin-St Jeor was published in 1990 and fitted to 498 healthy adults in Nevada — 247 women and 251 men, aged 19 to 78, spanning normal weight through obesity. It predicts resting expenditure within about 10% for most people in a population like that one. Ten percent of a 2,200 kcal maintenance is ±220 kcal a day, which is larger than the difference between two adjacent rows in the rate table.
- It has no term for body composition. Muscle is metabolically more expensive than fat, and two people at the same height, weight, age and sex with very different builds get the same answer here. If you know your body fat percentage, an equation that uses lean mass directly — Katch-McArdle — will usually beat this one.
- The activity multipliers are the weakest input. Five buckets cover a range that varies continuously, and the step from one to the next is worth 150 to 300 kcal a day. Self-reported activity also runs high in every study that has checked it against doubly labelled water. When in doubt, choose the lower bucket.
- Intake is estimated too. Food labels are allowed meaningful tolerances, home portions drift, and studies comparing self-reported intake against measured expenditure find under-reporting of 20% and more. Two estimates with error bars that wide will not agree on the first try.
- The equation has one sex term and two values. It was fitted to a binary variable and offers nothing else. If neither branch describes you, read both figures as brackets around an estimate and let your own data decide.
None of that makes the number useless. It is a starting hypothesis that is cheap to produce and easy to test: hold the target for two or three weeks, weigh consistently, and adjust the intake by 100 to 200 kcal against the trend. Measurement beats prediction, and the point of the prediction is to give measurement somewhere to start.
What this calculator assumes
- You are an adult. Mifflin-St Jeor was fitted to adults, and resting expenditure in a growing body follows different coefficients, so ages under 18 are refused rather than answered wrongly.
- You are not pregnant or breastfeeding. Both change energy needs in ways this equation has no term for.
- The activity multiplier already includes your training. Logging workouts separately and eating them back counts the same energy twice.
- Energy per unit of body mass is constant — 7,700 kcal per kilogram, 3,500 per pound. It is not, which is the whole subject of the section above.
- Weight change is all one kind of tissue. In reality the first week of any deficit is heavily water and glycogen, and part of what follows is lean mass, more of it the faster you go.
- Projected dates count whole calendar days in UTC from the start date you set, and round up. They assume perfect adherence and no metabolic adaptation, so they are the earliest plausible date rather than the likely one.
Calorie target FAQ
How many calories should I eat to lose weight?
Fewer than you burn — and the size of the gap is the only lever. This page starts from maintenance, then subtracts the energy that a chosen rate of loss represents: about 550 kcal a day for half a kilogram a week, or 500 kcal a day for a pound. Half a kilo or a pound a week is the rate most guidance settles on, because it is fast enough to see on a scale inside a month and slow enough that most of what comes off is fat rather than muscle. Faster is not better; it is just faster, and it costs more lean mass and more adherence.
Is 1,200 calories a day safe?
It is the number below which US and UK guidance stops treating a diet as something to run on your own. At 1,200 kcal (women) or 1,500 kcal (men) it becomes genuinely hard to hit protein and micronutrient needs from food, and the share of weight lost as lean tissue rises. Very-low-calorie diets do exist and they work, but they are run with medical supervision, monitoring, and often formula products — not from a web page. This calculator will show you a target under that line if the arithmetic produces one, and will tell you plainly not to take it.
Why has my weight loss stalled at the same calories?
Because maintenance is a function of your body mass, and your body mass went down. A lighter body costs less to run: less tissue to keep warm, less mass to move, and a smaller thermic cost of eating less food. What was a 550 kcal deficit at 70 kg is a smaller one at 65 kg, and eventually it is zero. That is not a failure of willpower or a broken metabolism — it is the arithmetic working exactly as it should. The fix is to recalculate at your current weight, not to eat less than the equation says.
Why is this number different from my watch or my fitness app?
Because they are estimating a different thing, or the same thing from different data. A wrist tracker infers energy expenditure from heart rate and motion and can be out by hundreds of calories a day in either direction. Apps differ in which prediction equation they use — Mifflin-St Jeor, Harris-Benedict, Katch-McArdle — and in how they bucket activity. None of them, including this page, measures anything. Treat every one of them as a starting hypothesis and let two weeks of scale data settle the argument.
Should I eat back the calories I burn exercising?
Not on top of the activity multiplier, or you count them twice. The multipliers here already include your training: choosing 'moderately active' has assumed three to five sessions a week. If you log a workout separately and eat it back as well, you have added the same energy to the ledger twice. If you would rather track exercise per session, pick the sedentary multiplier and add the sessions yourself — but be aware that both the multiplier and the watch tend to be generous.
Is a 500 calorie deficit really a pound a week?
It is the arithmetic of 3,500 kcal per pound of body tissue, and it holds for a while. What it cannot do is keep holding, because it assumes maintenance never moves. Over months, real loss falls behind the straight line — a paper by Kevin Hall put the long-run error at roughly half, meaning a deficit the linear rule says will remove 25 kg over a few years removes closer to half that before it flattens. The rule is a good first month and a bad first year.
Sources and review notes
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. “A new predictive equation for resting energy expenditure in healthy individuals.” American Journal of Clinical Nutrition, 1990 — the equation and the 498-adult sample it was fitted to
- Hall KD. “What is the required energy deficit per unit weight loss?” International Journal of Obesity, 2008 — the analysis showing the 3,500-calorie rule overpredicts long-run loss by roughly a factor of two
- National Institute of Diabetes and Digestive and Kidney Diseases — Body Weight Planner, a projection built on the dynamic model rather than the linear rule
- NIST Special Publication 811 — the exact inch and pound definitions used for the imperial conversion
The arithmetic is fixed: a published equation, five published multipliers, and two energy constants that have not moved since the 1950s. What does change is the guidance around them — the 1,200 and 1,500 kcal floors are conventions rather than findings, and a clinician working with you can and should override anything here.