Free calorie calculator

How much should you eat
to lose weight?

Get your personalized calorie target, see exactly when you'll reach your goal, and find out what happens if you eat more or less.

About you

Enter your details to calculate your daily calorie needs and weight loss target.

ft in
Activity level

How active are you on a typical week?

Your daily calorie target
—
calories per day
to lose 1 lb per week
Maintenance
—
cal/day
Daily deficit
—
calories
Goal date
—
🎚 Adjust your deficit
📅 Your weight loss timeline

    How to calculate a calorie deficit

    A calorie deficit occurs when you consume fewer calories than your body burns. To lose weight, you need to consistently eat fewer calories than your Total Daily Energy Expenditure (TDEE). This calculator uses the Mifflin-St Jeor equation — the most accurate formula for estimating calorie needs — to find your personal targets.

    What is TDEE?

    TDEE stands for Total Daily Energy Expenditure — the total number of calories your body burns in a day, including your basal metabolic rate (calories burned at rest) plus the calories burned through physical activity. Eating below your TDEE creates the deficit needed for weight loss.

    How big should your calorie deficit be?

    A 500 calorie/day deficit creates roughly a 1 pound per week loss — widely considered the sweet spot for sustainable fat loss while preserving muscle. A 250 calorie deficit produces about half a pound per week, which is gentler and easier to maintain. Deficits above 1,000 calories per day are generally not recommended as they can cause muscle loss, nutrient deficiencies, and metabolic adaptation.

    Does eating too little slow your metabolism?

    Yes — this is called metabolic adaptation. When you eat very few calories for an extended period, your body reduces its energy expenditure to compensate. This is why extremely aggressive deficits often produce diminishing returns over time. Moderate deficits (500–750 cal/day) with regular exercise help preserve muscle mass and minimize metabolic slowdown.

    What is BMR vs TDEE?

    BMR (Basal Metabolic Rate) is the number of calories your body needs just to stay alive — breathing, heart beating, organs functioning — if you did nothing but lie still all day. TDEE multiplies your BMR by an activity factor to estimate actual daily calorie burn. Most people should use their TDEE (not BMR) as their target to calculate a deficit from.

    Frequently asked questions

    How many calories should I eat to lose weight?
    It depends on your size, age, sex, and activity level. The calculator above gives you a personalized answer, but a common starting point is eating 500 calories below your maintenance level, which produces approximately 1 pound of fat loss per week. Most active women lose weight on 1,400–1,800 calories per day; most active men on 1,800–2,200 calories.
    How long does it take to lose 20 pounds?
    At a safe rate of 1 pound per week (500 calorie daily deficit), losing 20 pounds takes approximately 20 weeks (5 months). At 1.5 lbs per week it takes around 13–14 weeks. Use the "How long will it take?" tab above to calculate your specific timeline based on your deficit.
    Is 1200 calories a day enough?
    1,200 calories is considered the absolute minimum for most women and is too low for most men. While it can produce fast weight loss initially, very low calorie diets are difficult to sustain, can cause muscle loss, nutrient deficiencies, and fatigue, and often lead to rebound weight gain. Most experts recommend staying above 1,400–1,500 for women and 1,800 for men when possible.
    What happens if I eat at maintenance calories?
    Eating at your maintenance calorie level means your weight stays stable — you won't gain or lose fat. Maintenance calories are useful to know as a reference point and are ideal during periods of muscle building, recovery, or when you've reached your goal weight.
    How accurate is this calorie calculator?
    This calculator uses the Mifflin-St Jeor equation, which research has found to be the most accurate BMR formula for most people — typically within 10% of actual metabolic rate. The activity multipliers are estimates; actual calorie burn varies based on fitness level, genetics, and individual metabolism. Treat the result as a starting point and adjust based on real-world results over 2–3 weeks.
    Should I eat back exercise calories?
    If you selected an accurate activity level above, your exercise is already factored into your TDEE and you do not need to eat back workout calories. If you chose "sedentary" but exercise regularly, you may want to eat back a portion (50–75%) of calories burned during intentional workouts to avoid too large a deficit on active days.

    Medical disclaimer: This calculator provides general wellness estimates and is not a substitute for advice from a registered dietitian or physician. Consult a healthcare professional before making significant changes to your diet, especially if you have any medical conditions.