How to figure out maintenance calories

To figure out your maintenance calories—the amount you need to eat daily to maintain your current weight—you can use a formula and observe your habits. Start by calculating your Basal Metabolic Rate (BMR), which estimates the calories your body burns at rest. Use the Mifflin-St Jeor equation:
Men: BMR = 10 × weight(kg) + 6.25 × height(cm) – 5 × age + 5
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) – 5 × age – 161

Then multiply your BMR by an activity factor:
1.2 (sedentary), 1.375 (light activity), 1.55 (moderate), 1.725 (active), or 1.9 (very active).

This gives your Total Daily Energy Expenditure (TDEE), your estimated maintenance calories. You can also track your intake and weight for a week to fine-tune the estimate.