Estimate how many calories you may need per day from your age, sex, height, weight, and activity level, plus optional maintenance, weight-loss, and weight-gain targets. This is an estimate, not a measurement.
These figures are estimates for general informational use, based on a predictive equation and standard activity assumptions. This calculator does not diagnose any condition and is not a personalized nutrition or medical prescription.
Daily calorie needs vary based on age, sex, height, weight, activity level, and other individual factors. This calculator estimates your daily energy needs from those inputs using the Mifflin-St Jeor equation, then adjusts for activity. Your actual calorie needs may be higher or lower than the estimate shown.
A calorie calculator estimates how many calories a person may need each day based on factors such as age, sex, height, weight, and activity level. It works by first estimating resting energy expenditure — the energy your body uses at rest — and then scaling that figure by an activity factor to approximate total daily calorie needs. The result is a starting-point estimate for understanding maintenance, weight-loss, or weight-gain calorie targets, not a clinical prescription.
This page is the central resource for daily calorie needs on CalculatorSearch. For a deeper look at any one component, you can estimate your BMR, calculate your TDEE, calculate your macros, or find your protein target using the dedicated calculators linked throughout this page.
The primary figure is your estimated daily calorie needs — the approximate number of calories your body uses per day given your inputs. Alongside it, the calculator shows your estimated resting energy expenditure (the energy baseline before activity is added), the activity factor applied, and your estimated maintenance calories. If you selected a weight-loss or weight-gain goal, an adjusted target is shown as well. None of these figures are exact; they're reasonable starting points that you can refine over time based on how your own weight trend responds.
This calculator uses the Mifflin-St Jeor equation as the primary predictive equation for adults, which is generally described in the literature as an equation for estimating resting energy expenditure — often labeled "BMR" by consumer calculators, though it doesn't directly measure metabolism.
W = weight in kg · H = height in cm · A = age in years
This is a simplified calculator model. For a deeper breakdown of the activity-adjustment framework, see the TDEE Calculator.
Predictive equations like Mifflin-St Jeor are derived from population data, so individual error exists — your true resting energy expenditure could reasonably fall somewhat above or below the estimate. Activity multipliers are simplified categories that can't capture every real-world activity pattern, and calorie needs change over time as weight, activity, and physiology change. Measuring energy expenditure precisely requires specialized methods well beyond what any online calculator can do, so treat every figure here as an estimate rather than a measurement.
Example only — not a personalized medical recommendation.
These five categories are calculator assumptions, not physiological constants — real-world activity patterns are often more complicated than five neat buckets, so use whichever description is the closest fit.
| Activity level | Typical description | Multiplier | What it means |
|---|---|---|---|
| Sedentary | Little or no exercise, desk job | 1.20 | Close to resting energy expenditure alone |
| Lightly Active | Light exercise 1–3 days/week | 1.375 | Modest addition above resting energy |
| Moderately Active | Moderate exercise 3–5 days/week | 1.55 | Noticeable addition above resting energy |
| Very Active | Hard exercise 6–7 days/week | 1.725 | Substantial addition above resting energy |
| Extra Active | Very hard training or a physical job | 1.90 | Largest addition in this model |
Age is one direct input in the resting-energy equation, and it's also linked to broader changes in body composition, activity, and health status over time. There isn't a single table that reflects "the right number" for every person of a given age — age is one factor among several, and the calculator above accounts for it alongside your height, weight, and activity level.
The Mifflin-St Jeor equation uses different constants for men and women because it was derived from population data showing different average resting energy expenditure between the sexes at a given height, weight, and age. This reflects a population-derived prediction model, not a claim that biological energy expenditure is completely determined by sex.
Maintenance calories are an estimate of the energy intake that may maintain your current body weight under your current activity and physiological conditions. This is not a guaranteed number — actual maintenance intake can differ because energy expenditure varies between individuals and can change over time as your weight, activity level, or routine changes.
A calorie deficit means eating somewhat below your estimated maintenance calories. The calculator above can show an estimated target based on a selected rate of change, but this figure is a planning estimate rather than a guarantee — a fixed calorie-to-weight-change conversion doesn't fully represent real-world weight change, because the body adapts as weight and energy expenditure change over time. There's no single deficit or fixed calorie number that's right for everyone; extreme restriction isn't recommended, and sustainability matters as much as the number itself.
If you want a more individualized approach that accounts for how the body adapts during weight loss, the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) provides a Body Weight Planner tool built for that purpose — see the Sources section below.
A calorie surplus means eating somewhat above your estimated maintenance calories. As with weight loss, the amount and composition of weight gained — how much is muscle versus other tissue — vary between people and depend on factors like resistance training and protein intake. This calculator does not promise that weight gained will be muscle. For related planning, see the Macro Calculator, Protein Calculator, and TDEE Calculator.
These three terms describe your intake relative to your estimated maintenance calories, not exact outcomes:
| Term | Relationship to maintenance | Typical association |
|---|---|---|
| Calorie deficit | Below maintenance | Associated with weight loss |
| Maintenance | At maintenance | Associated with stable weight |
| Calorie surplus | Above maintenance | Associated with weight gain |
None of these describe a guaranteed rate of change — they describe a general direction. The calculator above lets you select a goal and a planning rate to see an estimated deficit or surplus target.
BMR, or resting energy expenditure, is the energy your body uses at rest, before any activity is added — see the BMR Calculator to estimate your BMR on its own. Your daily calorie needs build on that baseline by adding an activity factor.
| Term | Meaning |
|---|---|
| BMR / REE | Estimated energy required at rest |
| Daily calorie needs | Estimated total daily energy requirement |
| TDEE | Estimated total daily energy expenditure |
| Maintenance calories | Estimated intake associated with maintaining weight |
TDEE (total daily energy expenditure) is the broader concept behind the number shown on this page. This Calorie Calculator uses a simplified approach — resting energy multiplied by a single activity factor — to estimate daily calorie needs quickly. If you'd like the deeper breakdown of how total energy expenditure is modeled, calculate your TDEE on the dedicated TDEE Calculator.
Calories represent total energy; macronutrients describe how that energy is distributed among protein, carbohydrate, and fat. Each gram of a macronutrient provides a conventional amount of energy:
| Macronutrient | Energy per gram |
|---|---|
| Protein | 4 kcal/g |
| Carbohydrate | 4 kcal/g |
| Fat | 9 kcal/g |
| Alcohol | 7 kcal/g |
These are standard Atwater-factor conventions used on food labels and in nutrition science — useful general figures rather than a perfect measurement of every food. To turn your calorie estimate into a full breakdown, calculate your macros on the Macro Calculator.
Protein is one of the three macronutrients that contribute calories, providing about 4 kcal per gram under standard Atwater factors. Beyond its calorie contribution, protein plays a distinct role in muscle maintenance and satiety. For a personalized figure, find your protein target on the Protein Calculator or calculate protein intake on the Protein Intake Calculator. This page doesn't provide a personalized medical protein prescription.
Carbohydrates generally provide about 4 kcal per gram under standard Atwater factors and are often the largest energy source in a typical diet. To estimate your carbohydrate intake as part of your overall calorie target, see the Carb Calculator.
Dietary fat generally provides about 9 kcal per gram under standard Atwater factors — more than twice the energy density of protein or carbohydrate gram for gram. To calculate your fat intake alongside your other macronutrient targets, see the Fat Intake Calculator.
Fiber is a type of carbohydrate that's nutritionally important for digestion and satiety, but its actual energy contribution depends on the specific type of fiber and the labeling methodology used — it isn't always treated as contributing exactly zero calories. To calculate daily fiber needs alongside your calorie target, see the Fiber Calculator.
Sugar is a type of carbohydrate and contributes energy at the same 4 kcal per gram as other carbohydrates. It's useful to distinguish total carbohydrate, naturally occurring sugars, and added sugars, since they're tracked separately on nutrition labels — sugar intake is one contributor to your total calorie intake, not a separate figure from it. To check your sugar intake, see the Sugar Intake Calculator.
Sodium doesn't meaningfully contribute calories, but it's still relevant to overall dietary intake and health. Day-to-day scale-weight changes linked to sodium intake generally reflect fluid balance rather than a change in body fat. To calculate sodium intake, see the Sodium Calculator.
Calorie quantity is only one part of nutrition. Protein, fiber, fruits, vegetables, whole grains, healthy fats, micronutrients, and hydration all affect health outcomes and how satisfied you feel on a given calorie target — two people eating the same number of calories from very different foods can have quite different experiences and results.
Calorie density describes how much energy a food provides per unit of weight or volume. Foods with lower calorie density can make it easier to eat a satisfying volume of food within a given calorie target, though calorie density alone doesn't automatically produce weight loss — overall intake still matters.
A ketogenic approach changes how your calories are distributed among macronutrients — generally very low carbohydrate, moderate protein, and high fat — but total calorie intake still matters for weight management. If you're following or considering a ketogenic approach, calculate keto macros on the Keto Macro Calculator using your estimated calorie needs from above as a starting point.
Intermittent fasting changes when you eat rather than automatically determining how much you eat — your total calorie intake across your eating window remains the primary factor relevant to weight management. If you're planning a fasting schedule, you can plan an intermittent fasting schedule on the Intermittent Fasting Calculator.
Predictive equations estimate a population average, not your individual physiology. Differences in body composition, genetics, hormone status, medications, sleep, stress, and daily movement outside structured exercise (sometimes called NEAT) can all shift your real energy needs away from the calculated figure. This is expected, not a sign that the calculator or the equation is "wrong."
Your calorie requirements can change over time. As body weight, activity, training, appetite, and age change, resting energy expenditure and total energy needs tend to shift as well — the body doesn't behave like a perfectly static calorie equation, and adaptive changes in energy expenditure are one reason fixed, one-time calorie rules can become inaccurate as circumstances change.
Keep in mind that short-term scale changes can reflect water balance, digestion, and other day-to-day factors beyond body fat, so trends over a couple of weeks are more informative than any single weigh-in. This section is general guidance, not medical advice.
This general adult calculator isn't intended as a pregnancy nutrition prescription. Pregnancy calorie needs should be discussed with a qualified healthcare professional; the Pregnancy Calculator covers pregnancy-specific dating and milestone information.
Breastfeeding calorie needs also aren't captured by this general calculator, and a one-size-fits-all number wouldn't be appropriate here either — discuss individualized needs with a healthcare professional.
This calculator is built for adults. Growing children and teenagers have different nutritional needs, and adult equations and weight-loss targets shouldn't be applied automatically to them. See the Child BMI Calculator for pediatric BMI-for-age instead.
Energy needs can differ with age, body composition, activity, and health status. Older adults may find the general estimate here less precise, and any specific dietary changes are best discussed with a healthcare professional.
Training volume and recovery demands can make the simple activity multipliers used here less precise for athletes with structured, high-volume training. Treat the estimate as a rough starting point rather than a sports-nutrition prescription.
Conditions such as diabetes, thyroid disorders, kidney disease, and eating disorders, as well as certain medications, can affect nutrition and weight management in ways this general calculator doesn't account for. If you have a relevant medical condition, talk to a qualified healthcare professional before making significant changes to your calorie intake.
This calculator provides an estimate, not a measurement, a diagnosis, or personalized medical advice. It does not account for every individual medical or physiological factor, and results should be treated as a general, adjustable starting point. If a calculated goal target looks implausibly low relative to your resting energy estimate, the calculator will flag that rather than presenting it as a safe target — and in general, calorie targets well below your estimated resting energy expenditure are worth discussing with a qualified healthcare professional rather than pursuing on a self-guided basis.
Daily calorie needs are estimated using the Mifflin-St Jeor equation for resting energy expenditure, multiplied by an activity factor selected from five standard categories. Results are calculated from unrounded intermediate values and displayed as whole numbers to avoid false precision. Optional weight-loss and weight-gain targets apply a selected calorie adjustment to the maintenance estimate; they are planning estimates, not guarantees of a specific rate of weight change.
Sources referenced in developing this page:
Author: the CalculatorSearch team. Add a "Reviewed By" credit only once a genuinely qualified professional (e.g. a registered dietitian) has checked this content — do not publish the placeholder byline above as a real reviewer. Content last reviewed: September 2026.
This calculator performs its computation in your browser. Your age, sex, height, weight, and any goal information you enter are not sent to a server, stored in an account, or used for unrelated profiling — no account or email is required to use this tool.