Calorie Calculator
Daily calorie needs to maintain, lose, or gain weight — based on your BMR and activity level.
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Ready when you are
Adjust the inputs on the left to see your maintain weight.
Start with what your body burns at rest
Maintenance calories sound complicated. They aren't. Your body burns a baseline amount of energy just to keep you alive, breathing, pumping blood, holding your temperature steady, even while you sleep. That baseline is your BMR, the basal metabolic rate. Pile your daily activity on top and you get the total your body actually uses, often called TDEE.
Eat that total and your weight holds. Eat below it and you lose. Above it, you gain. Calorie planning really is that simple at its core, though the body has plenty of opinions about the details.
How the formula actually works
Most good calculators use the Mifflin-St Jeor equation, which has held up well in research. For men it reads: 10 times weight in kg, plus 6.25 times height in cm, minus 5 times age in years, plus 5. Women use the same line but subtract 161 at the end instead of adding 5.
That gives BMR. Then you multiply by an activity factor. Roughly 1.2 if you mostly sit, around 1.375 for light exercise, near 1.55 if you're moderately active a few days a week, and 1.7 or higher for hard training. The factor is an honest estimate, so be truthful about how much you really move.
A real number to anchor it
Picture a 30-year-old woman, 65 kg, 162 cm tall, with a desk job and a couple of light walks a week.
BMR works out as: 10 times 65 is 650, plus 6.25 times 162 is 1012.5, minus 5 times 30 is 150, then minus 161. Add it up and you get about 1351 calories a day at complete rest.
Now apply a light-activity factor of 1.375. That's roughly 1351 times 1.375, which lands near 1858 calories. So she holds her weight around 1850 a day. To drop about half a kilo a week, she trims roughly 500 from that and aims for 1350 to 1400.
Treat the result as a sensible starting point
Why 500? Because half a kilo of body fat stores around 3,500 calories, and 500 a day across a week comes to that. Neat arithmetic, but bodies aren't spreadsheets. Metabolism shifts, water weight wobbles, and the scale lies on any single morning.
So use your number as a launch pad, not gospel. Eat to it for two or three weeks, watch the weekly trend rather than daily jumps, and adjust. And don't crash too low. Dropping under about 1,200 a day for women or 1,500 for men can leave you short on nutrients and tired. If you've got a thyroid issue, diabetes, or you're pregnant, check with a doctor or dietitian before cutting. This is a guide, not a prescription.
Calorie Calculator — frequently asked questions
How many calories should I eat a day to lose weight?
Work out your maintenance calories first, then subtract about 500 a day for steady loss of roughly half a kilo a week. So if you maintain at 2,000, you'd aim for around 1,500. Avoid going too low, since dropping under 1,200 for women or 1,500 for men often backfires with fatigue and lost muscle. Slow and steady holds up far better long term.
What is the Mifflin-St Jeor formula?
It's the equation most dietitians trust for estimating BMR. For men it's 10 times weight in kg, plus 6.25 times height in cm, minus 5 times age, plus 5. Women use the same line but subtract 161 instead of adding 5. It gives your resting calorie burn, which you then multiply by an activity factor to reach your full daily need.
What is TDEE and how is it different from BMR?
BMR is what your body burns at complete rest, just keeping the basics running. TDEE, your total daily energy expenditure, is that baseline plus everything else, including walking, working, exercise and even digesting food. You reach TDEE by multiplying BMR by an activity factor. TDEE is the number that matters for planning meals, because it reflects how much you actually use in a real day.
Why am I not losing weight despite eating in a deficit?
A few things commonly explain it. Calorie counts on packets and apps are often underestimated, so the real intake is higher than you think. Water retention can mask fat loss for weeks. Activity levels also drift down quietly when you're dieting. Give any plan three to four weeks and track the weekly trend. If nothing moves, a doctor can check thyroid or other causes.
How accurate are calorie calculators?
They give a solid estimate, usually within about 10 percent for most people, but they can't be exact. The formulas use averages, and real metabolism varies with muscle mass, genetics, hormones and how active you truly are. The activity factor is the biggest source of error, since people tend to overrate their movement. Use the figure as a starting point and adjust based on real results.
Should I eat back the calories I burn during exercise?
It depends on how your maintenance number was built. If you already chose a higher activity factor that includes your workouts, eating them back again double counts and stalls progress. If you used a sedentary baseline and log exercise separately, eating some back can make sense. Most people find it simpler to pick one honest activity level and leave exercise calories out of the daily maths.
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Results from this calculator are estimates for informational use only — not financial, medical, or professional advice. Read our full disclaimer before acting on any number you see here.