Is it maximum how much we burn in a day?
A TDEE calculator will give you a quick estimate. The best way would be to track the amount of calories you consume and measure your body weight and see how your body weight changes.
Some apps, like MacroFactor, do these calculations for you.
Really depends on your goals. If you want to lose weight than your Intake needs to be less than what you burn in a day. If you want to maximize muscle growth and just generally gain weight than it should be slightly higher than what you burn in a day.
Generally, TDEE formulas get you in the ballpark but are not overly accurate. A TDEE formula based put me as 3500kcal/day, however, subsequent tracking with an app called “MacroFactor” (/r/MacroFactor ) which uses my weight and calorie intake over time to more accurately estimate my TDEE has it down to 3000kcal/day.
Consistently eating at 500kcal over my TDEE would lead to an theoretical 1lb/week gain.
By testing. These calculators that you find online can be completely wrong. Go with what you think you need (I know it’s not easy, but here you could use a calculator as a reference point) and then weigh yourself each day while eating the same amount of calories. Over the curse of a few weeks, you’ll see if you need to eat more or less. From there, you can calculate, depending on your goals. 3500kcal above your maintenance calories per week equals 1 lbs of weight gain.
The only way to really know is to count calories for a few weeks and compare that to weekly weight avarages over 2-3 weeks.
An online calculator can give you a starting point, but they can also be wildly off. Lots of individual variation.
It depends on your goals. Are you trying to lose weight (fat)? Or are you trying to build muscle? Maintain? Shift body composition without changing the scale much? All of those will have an impact on your nutrition & calories-in strategy.
Next, there are online calculators you can use to estimate your BMR or TDEE. You can use that as a starting point. However, these numbers are based on averages for people of similar weight & height, and they are not a hard science. There are many things that can influence overall metabolism from person to person.
So the best thing to do is use these calculators as a starting point. Add or subtract calories based on your goal (muscle? Fat loss?) or leave it the same to maintain. Then track your food intake as accurately as possible for a few weeks, ideally using a food scale.
Over a few weeks, if you have diligently tracked you will have a pretty good idea of how many calories you have consumed. Now look at your weight—has it changed? If it stayed pretty close to the same, then you can be confident that you have eaten close to maintenance.
Want real world. Let your body do it. Eat very low fat, don’t stress about protein, focus on fruit and real carbohydrates. If your getting hungry eat. Stay very hydrated and get good sleep. Your hormones and body will signal eating to how it wants. Watch out for the orthorexic calorie counting.
If your going to weigh yourself do it same time 3 days in a row every month.