FitCalculationA calorie calculator estimates your daily calorie needs from your age, sex, height, weight, and activity level. The figure it produces is a rough estimate of maintenance calories — not an exact physiological requirement.
Calorie Calculator – Calculate Your Daily Calorie Needs
Estimate your daily calorie needs and maintenance calories based on your age, sex, height, weight, and activity level.
What this calculates
The same maintenance-calorie estimate as the TDEE calculator, presented as the number to eat to hold weight steady.
What is a calorie calculator?
Because the primary result is maintenance calories, this tool also works as a maintenance calorie calculator: enter your own details to get an estimate built around your body and your activity level, then refine it against how your weight actually changes.
How many calories do I need per day?
Daily calorie needs differ from person to person. Body size, age, sex, and activity level all change how much energy you use, so no single calorie figure is appropriate for everyone.
The calculator's primary result is your estimated maintenance calories: the calories you would need each day to hold your weight steady at the activity level you selected. Your own inputs drive the number, which is why it will differ from someone else's.
How is a calorie calculator calculated?
Step 1 · Estimate BMR
BMR is the energy your body uses at complete rest. This calculator estimates it first, using the Mifflin-St Jeor equation:
Men: 10 × kg + 6.25 × cm − 5 × age + 5
Women: 10 × kg + 6.25 × cm − 5 × age − 161
Step 2 · Apply your activity factor
That BMR is then multiplied by the activity factor for your chosen activity level, producing your estimated maintenance calories:
Maintenance calories = BMR × activity factor
- Sedentary×1.2
- Lightly active×1.375
- Moderately active×1.55
- Very active×1.725
- Extra active×1.9
What are maintenance calories?
Maintenance calories are an estimate of the daily food intake expected to keep your body weight steady at the activity level you stated. Eating roughly around that figure should keep your weight broadly stable.
Your actual maintenance can differ from the estimate — metabolism, body composition, and day-to-day movement all play a part. The practical fix is to watch your real-world weight trend over a couple of weeks and adjust your intake to match what is actually happening.
Can I use a calorie calculator to lose weight?
Yes, as a starting point. Weight loss generally requires a sustained energy intake below your total energy expenditure, and your estimated maintenance calories show where that expenditure sits.
A calorie calculator for weight loss is therefore a maintenance estimate plus a planned reduction. This page stays informational: a modest, consistent deficit is the usual approach, your weight trend is the guide, and deficit-specific calculations will be handled by the future Calorie Deficit Calculator.
How accurate is a calorie calculator?
Results are estimates. The calculator combines predictive equations — Mifflin-St Jeor for BMR — with an activity level you select, so the output depends on both your inputs and how accurately you described a typical week.
Individual energy expenditure varies, and real-world weight trends can differ from any prediction. Treat the figure as a starting point, track your weight for two to three weeks, and adjust from there. This tool is for general information and is not medical advice.
Calorie FAQ
What is a calorie calculator?
A calorie calculator estimates your daily calorie needs from your age, sex, height, weight, and activity level. The figure it gives is an estimate of maintenance calories — roughly the intake that would hold your weight steady — not a measurement of your body.
How many calories do I need per day?
It depends on your body size, age, sex, and how active you are, so no single number suits everyone. The calculator's primary result is your estimated maintenance calories for the activity level you selected — a sensible baseline for planning your own intake.
What are maintenance calories?
Maintenance calories are an estimate of the daily intake that would keep your weight steady at the activity level you have stated. Eating around that figure should keep your weight broadly stable, though your true maintenance can differ, so fine-tune from your real weight trend.
How does a calorie calculator work?
It works in two steps: first it estimates your BMR — the energy your body uses at complete rest — then multiplies it by an activity multiplier that matches your typical week. The result is your estimated maintenance calories for the day.
How is my calorie requirement calculated?
Your BMR is worked out with the Mifflin-St Jeor equation from your sex, age, height, and weight, then scaled by an activity multiplier for the level you choose: maintenance calories = BMR × activity multiplier. Both steps rely on the inputs you provide.
Is a calorie calculator accurate?
It is useful as an estimate, not a measurement. The result combines a predictive equation with the activity level you select, so it cannot capture everything about your individual expenditure. Treat the number as a baseline and adjust from how your weight actually changes.
How accurate are calorie calculator results?
Calorie calculator results are estimates, not lab measurements. They depend on the accuracy of your inputs and how well the chosen activity level reflects your real week, and predictive equations vary between individuals. Your weight trend over a few weeks is the better guide.
Can I use a calorie calculator to lose weight?
Yes, as a baseline. Weight loss generally requires eating less than you expend over time, and your estimated maintenance calories show where that level sits. This page stays informational — it does not calculate a deficit for you.
Can I use a calorie calculator to gain weight?
Yes. Weight gain generally comes from eating more than you expend over time, so your estimated maintenance calories act as the reference point — a small, steady surplus above that figure is the usual approach to gaining gradually.
Does my calorie requirement change as my weight changes?
Yes. Your BMR is calculated partly from your current weight, so as your weight changes your estimated requirement changes with it. Recalculating with updated numbers keeps the figure in step with where you are now.
How often should I recalculate my calorie needs?
Recalculate whenever your weight or your usual activity level changes noticeably, or every few weeks as a routine check. If your weight has been steady for two to three weeks, your current estimate is still a fair guide.
What's the difference between BMR and maintenance calories?
BMR — basal metabolic rate — is the energy your body uses at complete rest, with no activity included. Maintenance calories cover a full day at your chosen activity level, so BMR is one component: this calculator estimates BMR first, then scales it with an activity multiplier.