How many calories you should eat
The honest answer is: it depends on your body, your activity and your goal, which is exactly what this calculator works out. It estimates your maintenance calories (the amount that keeps your weight stable) using the Mifflin-St Jeor equation and your activity level, then shows your target for every goal so you can see the whole picture, not just a single figure.
For weight loss, a deficit of around 500 calories per day produces roughly 0.45 kg (1 lb) of loss per week, fast enough to stay motivated, slow enough to keep muscle and energy. For muscle gain, a 300 to 500 calorie surplus supports lean gains without excessive fat. To maintain, you eat at maintenance. The results panel lays all of these out for your numbers. The target is the easy part; the discipline to hit it daily is what gets results.
Why you shouldn't just eat as little as possible
Crash diets feel productive and rarely are. Drop calories too far and you lose muscle alongside fat, your energy and training tank, hunger becomes unmanageable, and the weight comes back the moment normal eating resumes. That's why this calculator applies a sensible floor (around 1,200 calories for women and 1,500 for men) and steers you toward a moderate deficit instead of an extreme one.
A smaller deficit you can hold for months beats an aggressive one you abandon in two weeks. Consistency is the whole game. If you've stalled despite eating carefully, the issue is usually accuracy or consistency rather than needing fewer calories. Read overcoming weight-loss plateaus for what to check first.
Turning a calorie target into results
Calories decide whether you lose or gain; protein and macros decide whether that change is muscle or fat, and whether you feel good getting there. Once you have your number here, run it through the macro calculator to split it into protein, carbs and fat.
Then the only thing that matters is consistency, and that is exactly what Macroo is built to enforce. Snap a photo or log a meal in plain English, watch your remaining calories update instantly, and let daily check-ins, streaks and coins keep you honest. It's a commitment device for your nutrition, so staying under your target stops being willpower and starts being routine. Free to start, with an optional Pro plan.