Calorie Calculator: Your BMR, TDEE and Daily Target
Estimate the energy your body burns at rest, the energy you burn across a whole day, and a daily calorie target for losing, maintaining, or gaining weight — with a macro breakdown to go with it. Choose Mifflin-St Jeor, revised Harris-Benedict, or Katch-McArdle, in metric or imperial. These are estimates for general information, not medical advice.
BMR
1,400kcal/day
At complete rest
TDEE
1,925kcal/day
BMR × 1.375
Daily target
1,925kcal/day
Maintain weight
Macros at 1,925 kcal
Protein · 30%
144g
578 kcal · 4 kcal/g
Carbs · 40%
193g
770 kcal · 4 kcal/g
Fat · 30%
64g
578 kcal · 9 kcal/g
These are estimates, not prescriptions. Equations predict group averages and individual needs vary by roughly 10% either side even for people with identical measurements. This tool is general information, not medical or dietary advice. If you are pregnant or breastfeeding, under 18, over 65, have a medical condition or a history of disordered eating, or are taking medication that affects appetite or metabolism, talk to a doctor or a registered dietitian before changing what you eat. Everything runs in your browser; nothing you enter is sent anywhere.
TL;DR
Your BMR is what you burn doing nothing at all. Multiply it by an activity factor between 1.2 and 1.9 and you get your TDEE — roughly what you burn in a full day. Eat around your TDEE to hold steady, a few hundred calories under it to lose slowly, a few hundred over it to gain. Every number here is an estimate: two people with identical measurements can genuinely differ by around 10% either side, so treat the result as a starting point and adjust it against what the scale and the tape measure actually do over three or four weeks. The calculator will not take you below 1,200 kcal (female) or 1,500 kcal (male), because eating less than that is not something to attempt without medical supervision. This page is general information, not medical or dietary advice.
BMR and TDEE are not the same number
BMR (basal metabolic rate)is the energy your body spends staying alive with no activity at all: keeping your heart beating, your lungs working, your brain running, your body temperature steady. For most adults it accounts for somewhere around 60–70% of everything they burn in a day. It is not a target to eat at — it is the floor of the calculation.
TDEE (total daily energy expenditure) adds everything else: deliberate exercise, walking to the bus, standing up, fidgeting, and the energy cost of digesting food. The calculator gets there the standard way, by multiplying BMR by an activity factor:
The daily targetis then your TDEE plus or minus the adjustment for your chosen goal. A 500 kcal daily difference is the conventional figure for about 0.5 kg (1 lb) a week, and a 1,000 kcal difference for about 1 kg (2 lb). That arithmetic comes from the old rule that a kilogram of body fat stores roughly 7,700 kcal — useful for setting a starting number, but it consistently overstates how much you will actually lose over months, because your body adapts as you go. More on that below.
The five activity multipliers, in plain English
Picking the activity level is where most people get their answer wrong, usually by choosing one step too high. The labels are vague on purpose, so here is what each one looks like in an ordinary week — and what it does to the result for our worked example (a 30-year-old woman, 68 kg, 165 cm, BMR 1,400 kcal).
| Level | × | What a typical week looks like | TDEE |
|---|---|---|---|
| Sedentary | 1.2 | Desk job, car or transit commute, no planned exercise. Under about 5,000 steps a day. | 1,680 |
| Lightly active | 1.375 | Desk job plus 1–3 sessions a week (a gym visit, a run, a long walk), or a job with regular walking. | 1,925 |
| Moderately active | 1.55 | Real training 3–5 days a week, 45–60 minutes a session, and a reasonably active rest of the day. | 2,170 |
| Very active | 1.725 | Hard training 6–7 days a week, or a physically demanding job plus regular exercise. | 2,415 |
| Extra active | 1.9 | Manual labour all day, twice-daily training, or an athlete in a heavy training block. | 2,660 |
Note how much rides on this one dropdown: for the same person, sedentary and extra active are nearly 1,000 kcal apart. If you are between two levels, the more useful habit is to choose the lower one and let three or four weeks of real-world results tell you whether to move up.
Which BMR formula should you pick?
All three equations here are legitimate and widely used; they simply make different assumptions about what predicts your metabolism. The last column runs each one for the same person — that 30-year-old woman, 68 kg, 165 cm, at 25% body fat — so you can see how far apart they land.
| Formula | Inputs it uses | Pick it when | BMR |
|---|---|---|---|
| Mifflin-St Jeor (1990) | Weight, height, age, sex | Almost always. It is the default here and the one most dietitians reach for first. | 1,400 |
| Revised Harris-Benedict (1984) | Weight, height, age, sex | You want to cross-check, or you are comparing against an older source that used it. | 1,458 |
| Katch-McArdle | Weight and body fat % only — no height, no age, no sex | You have a genuinely measured body fat figure (DEXA, calipers), especially if you are lean and muscular or carrying a lot of fat. | 1,472 |
The equations themselves, if you want to check the arithmetic by hand (weight in kg, height in cm, age in years):
Katch-McArdle is only as good as your body fat number. A guess from a bathroom smart scale can be off by several percentage points, which moves the BMR by 50–100 kcal — so if you are guessing, Mifflin-St Jeor is the safer choice.
A worked example, from BMR to dinner plate
Take that same 30-year-old woman: 68 kg, 165 cm, a desk job with a couple of gym sessions a week, aiming to lose about 0.5 kg a week.
- BMR — 10×68 + 6.25×165 − 5×30 − 161 = 680 + 1,031.25 − 150 − 161 = 1,400 kcal.
- TDEE — lightly active, so 1,400 × 1.375 = 1,925 kcal. That is roughly what she burns on an ordinary day.
- Target — 1,925 − 500 = 1,425 kcal a day for slow loss. That sits above the 1,200 kcal floor, so no warning appears.
The macro panel then splits that target into grams using 4 kcal per gram for protein and carbohydrate and 9 kcal per gram for fat. Here is what her 1,425 kcal looks like under each of the three splits the tool offers — the same energy, arranged differently:
| Split | Protein | Carbs | Fat |
|---|---|---|---|
| Balanced (30 / 40 / 30) | 107 g | 143 g | 48 g |
| Higher protein (40 / 30 / 30) | 143 g | 107 g | 48 g |
| Lower carb (35 / 20 / 45) | 125 g | 71 g | 71 g |
None of these three is the “correct” one. Research comparing diets at matched calories generally finds the differences between them are small, and that the split people can actually stick with is the one that works. Adequate protein is the part with the most consistent evidence behind it, because it helps preserve muscle while you are in a deficit and tends to keep people fuller. There are no forbidden foods in any of these columns — they are arithmetic, not a moral scheme.
Why your real number will drift from this one
These equations were built by measuring a lot of people and fitting a line through the middle. They predict the averageperson with your measurements well, and any specific person less well. In validation studies, predicted resting metabolic rate typically lands within about 10% of the measured value for most people — which on a 2,000 kcal TDEE is a spread of roughly 200 kcal in either direction. Two people who are the same age, height, weight, and sex can honestly need different amounts of food.
Several things push you off the line: thyroid function and other medical conditions, some medications, how much muscle you carry relative to fat, ancestry, and how much you move without noticing — the fidgeting-and-pacing category that varies enormously between individuals. Then there is adaptation. As you lose weight there is simply less of you to maintain, so your TDEE falls; people also tend to move a little less, unconsciously, when eating less. This is why a straightforward 500 kcal deficit rarely produces a tidy half-kilo every week for six months.
The practical answer is to treat the number as a hypothesis. Eat around it for three to four weeks, weigh yourself under the same conditions a few times a week and look at the weekly average rather than any single day, and then adjust by 100–200 kcal based on the trend. That measured, personal number beats any equation, including this one. Recalculate after every 5–10 kg of change, since the inputs have moved.
The floors, and who should talk to a professional first
If the goal you choose would push your target below 1,200 kcal for women or 1,500 kcal for men, the calculator raises it back to that floor and tells you it did. Those thresholds are the conventional lower limits for eating without clinical supervision. Below them it becomes genuinely difficult to get enough protein, vitamins, and minerals from food, and very-low-calorie diets are a medical intervention — something done with a doctor monitoring you, not something to arrange for yourself from a web page. If a goal keeps triggering that warning, the honest fix is a slower rate of loss, not a smaller plate.
A general calorie estimate is also the wrong tool for a number of situations. Please speak to a doctor or a registered dietitian before changing what you eat if you are:
- Pregnant or breastfeeding — energy and nutrient needs are higher and change through pregnancy, and a deficit is generally not appropriate.
- Under 18 — children and teenagers are still growing, and these adult equations do not apply to them.
- Over 65 — preserving muscle and bone matters more than the number on the scale, and protein needs are often higher than a generic split suggests.
- Living with a medical condition — diabetes, thyroid or kidney disease, heart conditions, and digestive disorders all change the answer.
- Taking medication that affects appetite or metabolism — including thyroid medication, steroids, some psychiatric medications, and GLP-1 drugs.
- Recovering from, or living with, disordered eating — calorie targets and tracking can be actively harmful here, and support from a clinician is worth more than any calculator.
Everything on this page is general information to help you understand how the arithmetic works. It is not medical or dietary advice, it cannot account for your individual health, and it is not a substitute for a conversation with a qualified professional who can.
Frequently asked questions
How many calories should I eat a day to lose weight?
Start from your TDEE and subtract a modest amount. A 500 kcal daily deficit is the usual starting point and corresponds to roughly 0.5 kg (1 lb) a week on paper. Larger deficits are harder to sustain, cost you more muscle, and rarely produce proportionally faster results, because your body adapts. Whatever the calculator says, do not go below 1,200 kcal (women) or 1,500 kcal (men) without medical supervision, and adjust after three or four weeks based on what actually happened rather than what the equation predicted.
What is the difference between BMR and TDEE?
BMR is the energy you would burn lying still all day doing nothing — the cost of simply being alive, typically around 60 to 70 percent of your daily total. TDEE is BMR multiplied by an activity factor between 1.2 and 1.9, and it covers everything else: exercise, walking around, standing, fidgeting, and digesting food. TDEE is the number to compare your eating against. BMR is an input to it, not a target to eat at.
Is the Mifflin-St Jeor equation accurate?
It is the most accurate of the widely used prediction equations for the general adult population, which is why it is the default here and the one most dietitians reach for. Accurate does not mean exact: it lands within about 10 percent of measured resting metabolic rate for most people, so on a 2,000 kcal day that is a spread of roughly 200 kcal either way. It is a good starting estimate, not a measurement.
Why does another website give me a different calorie number?
Usually because it uses a different BMR equation, a different set of activity multipliers, or a different assumption about how many calories a kilogram of body fat represents. A 100 to 200 kcal gap between two reputable calculators is completely normal and does not mean either is broken. Pick one, follow it for a few weeks, and let your own results settle the question rather than averaging websites.
Is 1,200 calories a day too low?
For many adults, yes. 1,200 kcal is a conventional floor rather than a recommendation, and it is the point below which this calculator stops. Getting adequate protein and micronutrients at that level is difficult, and very-low-calorie diets belong under clinical supervision. If your goal keeps pushing the target down to the floor, choose a slower rate of loss instead, and speak to a doctor or registered dietitian before eating that little.
Do macros matter, or is the calorie total enough?
Total energy is what drives weight change, so if you only track one thing, track calories. Macros affect how that experience feels and what you keep. Adequate protein has the most consistent evidence behind it, because it helps preserve muscle in a deficit and tends to keep people fuller. Beyond that, studies comparing diets at matched calories find modest differences between splits, so choose the one you can live with rather than the one that sounds most disciplined.