You don’t need extreme precision when counting calories. The trick is to A develop a reasonable baseline for breaking even at your weight and activity level. Then B make a significant reduction sufficient to lose weight in a reasonable timeframe. You can call them calories or magic beans, as long as the energy ratio is about right that’s plenty.

Really, the difference between say 2,500 calories a day and 1,800 is about the magnitude you want and not that hard to differentiate.