How many calories should I eat to lose weight?

1 lb of fat = 3,500 calories. To lose 1 lb/week, eat 500 calories/day below your TDEE. To lose 2 lb/week, eat 1,000 calories/day below TDEE. Never go below 1,200 calories/day without medical supervision — metabolic adaptation slows weight loss.

TDEE (Total Daily Energy Expenditure) = BMR + activity + thermic effect of food. BMR alone is calories at rest; TDEE includes walking, exercise, and digestion. Weight loss = eat below TDEE. Weight gain = eat above TDEE.

Should I eat back exercise calories?

Fitness trackers overestimate calories burned by 15–30%. Better approach: don't eat back exercise calories unless you're eating very little (under 1,500/day) and feeling sluggish. Let the scale guide you — if you're losing, keep your routine.

How accurate are calorie calculators?

Calorie calculators are estimates ±15–20%. Your actual needs depend on genetics, microbiome, sleep, stress, and hormones. Use the estimate as a starting point, then adjust based on weight changes over 2–3 weeks.

Calorie Calculator (2026) – Free Daily Calories TDEE Tool

How to Use This Calorie Calculator

Enter your age, sex, weight, height, and activity level. Select your goal: lose weight, maintain, or gain muscle. The calculator instantly shows your daily calorie target, BMR, and TDEE. Adjust the activity level if your exercise routine varies.

How Daily Calorie Needs Are Calculated

This calculator uses the Mifflin-St Jeor equation — the most validated formula for estimating Basal Metabolic Rate (BMR) in adults. BMR is then multiplied by an activity factor to get TDEE (Total Daily Energy Expenditure) — the actual calories you need each day.

Your goal adjustment is applied on top of TDEE: subtract 500 calories/day for ~1 lb/week weight loss, add 300 calories for lean muscle gain, or eat at TDEE for maintenance.

The Mifflin-St Jeor Equation

Male BMR = 10×weight(kg) + 6.25×height(cm) − 5×age + 5 Female BMR = 10×weight(kg) + 6.25×height(cm) − 5×age − 161 TDEE = BMR × Activity Factor

Activity Multipliers Explained

Level	Multiplier	Description
Sedentary	1.2	Desk job, no intentional exercise
Lightly Active	1.375	Light exercise 1–3 days/week
Moderately Active	1.55	Moderate exercise 3–5 days/week
Very Active	1.725	Hard exercise 6–7 days/week
Extra Active	1.9	Athletes, physical labor, or twice-daily training

Frequently Asked Questions

The Mifflin-St Jeor equation predicts BMR within 10% for most people. The larger source of error is the activity multiplier — people consistently overestimate their activity level. If results don't match your experience, try the next lower activity setting.

A 500-calorie daily deficit produces approximately 1 lb (0.45 kg) of weight loss per week — a sustainable, evidence-based rate. Deficits larger than 1,000 calories/day risk muscle loss and metabolic adaptation. Deficits below 300 calories/day produce slow but very sustainable loss.

BMR (Basal Metabolic Rate) is the calories your body burns at complete rest — just to maintain basic functions. TDEE (Total Daily Energy Expenditure) adds calories burned through all daily activity. TDEE is the number you should base food intake on, not BMR.

For active adults, 1.6–2.2 grams of protein per kilogram of body weight is the evidence-based range for muscle retention and growth. For weight loss specifically, higher protein (2.0–2.4 g/kg) helps preserve muscle mass during a calorie deficit.