Nobody can answer this question without more information. This number is entirely based on the approach as well as your goals. Typically if you are goaling to increase muscle you want to be in a caloric surplus. If you are goaling to cut down weight you want a caloric defecit. So the first thing you want to do is find your resting metabolic rate. It is often an interchangable word with basal metabolic rate, so you can use a BMR calculator. There are many different formulas with the Harris Benedict being the most common. It is a good idea to get a few different numbers from various formulas and take an average.

Harris Benedict Formula(Revised)

Males: 88.362 + (13.397 x Weight [kg]) + (4.799 x Height [cm]) – (5.677 x Age)
Females: 447.593 + (9.247 x Weight [kg]) + (3.098 x Height [cm]) – (4.33 x Age)

Knowing this is just the start as it is just not that simple. Understand that excessive decreases in calories can affect the metabolism as well. These formulas can be thought of as your metabolism under ‘normal circumstances’. Physiology and your hormones will also play a large part of the control of metabolism and muscle building. 

Then you have general nutrition to consider which stretches past the simple ‘calories in vs calories out’. Focusing on simply just calories ignores the specifics of macronutrients(carbs, protein and fat) and micronutrients(vitamins and minerals).

Remember that a calorie is a unit of measurement that measures energy consumption. That energy will come from either a carb, protein or fat. This means that if you are consuming less calories than your BMR does not mean that the extra calories burned by the body will be fat. It could be either of the 3 and will likely be carbs as this is the quickest pathway to creating energy. Please note that the body does not actually use ‘calorie’,’protein’, ‘fat’ or ‘carbs’ as energy, they use these to convert into usable energy forms in the body known as ATP.

Also consider that weight is made up of many things in the body not just fat and not just muscle. As a result your weight can fluctuate a large amount daily, especially if you do a lot of physical activity. Depending on when you take measurements and the device(how accurate) used to measure can lead to a lot of inaccurate variability when you are using formulas. So understand that these formulas are always just estimates. Furthermore not every formula itself is the most accurate or complete.

If you are consuming more calories than your BMR also does not mean that is how much fat you will be gaining. Calories can be either carb, protein or fat. Dietary fats are a little different than stored body fat. Although fat equates to more calories per gram, eating more of it will not necessarily equate to storage. It does have a function as a nutrient in the body. Typically it is actually excessive carbs that will convert into stored body fat. So the particular ‘calorie’ you consume matters and not all calories are created equally.

If you are comsuming more calories for the purpose of building muscle then you need to consider that muscle is built with protein as the building blocks. But a house does not get built with simply just bricks alone, it needs forms, cement, tools, people to build etc… There are other things involved with the muscle building process such as androgens like testosterone which requires nutrients like zinc. Many of these nutrients involved in the process are micronutrients which do not actually carry any calories. Calories are only fat, carbs and protein. So you may be consuming the right amount of calories for your goal, however the type of calories consumed matter and micronutrients also matter in the overall process. It is a little more complex than just calories in the game.