Weight Loss Calorie Calculator
Calculate exactly how many calories to eat daily to lose weight at a safe, sustainable pace.
Quick Answer
To lose 1 lb/week: eat 500 calories less than your TDEE. For a 2,000 cal TDEE, that means eating 1,500 cal/day.
Calculate Weight Loss Calories
Frequently Asked Questions
How Weight-Loss Calories Are Set: TDEE Minus Deficit
Weight loss comes down to one equation: eat fewer calories than you burn. Your Total Daily Energy Expenditure (TDEE) is the number of calories you burn in a day. Subtract a deficit from that number, and you get your daily weight-loss calorie target.
Weight Loss Target = TDEE − Daily Deficit
One pound of body fat contains roughly 3,500 calories. To lose 1 pound per week, you need a daily deficit of 500 calories (500 × 7 = 3,500). To lose 2 pounds per week, you need a 1,000-calorie daily deficit.
TDEE itself is built from two parts: your Basal Metabolic Rate (BMR), the calories your body burns at rest, plus an activity multiplier that accounts for movement and exercise.
Safe Rates: 0.5–1% Body Weight Per Week
The CDC recommends a weight-loss rate of 1 to 2 pounds per week for most adults. Expressed as a percentage of body weight, that is roughly 0.5 to 1 percent per week.
- 0.5 lb/week — gentle, ideal for smaller individuals or maintenance transitions.
- 1 lb/week — the standard sustainable rate for most adults.
- 1.5–2 lb/week — aggressive; requires higher protein and monitoring for muscle loss.
Losing faster than 2 pounds per week increases the risk of muscle loss, nutrient deficiency, gallstones, and rebound weight gain. Heavier individuals can safely lose at the higher end; lighter individuals should target the lower end.
Deficit Options Table With Timelines
Choose a deficit based on your goal rate. Each row shows the daily deficit and what to expect.
| Target Rate | Daily Deficit | What to Expect |
|---|---|---|
| 0.5 lb/week | 250 cal/day | Gentle; best for maintenance transitions |
| 1 lb/week | 500 cal/day | Recommended sustainable rate |
| 1.5 lb/week | 750 cal/day | Moderate; needs protein focus |
| 2 lb/week | 1,000 cal/day | Aggressive; monitor for muscle loss |
Source: 1 lb of body fat ≈ 3,500 kcal (Hall et al., NIH). CDC safe-rate guideline: 1–2 lb/week.
How the Calculator Works: Inputs Explained
This calculator uses the Mifflin-St Jeor equation, the most accurate predictive formula for BMR according to the Academy of Nutrition and Dietetics. Here is what each input does:
Age, Sex, Weight, Height
Fed into the Mifflin-St Jeor BMR equation. Men's and women's equations differ by a constant because of differences in lean mass.
Activity Level
Multiplies your BMR by a physical activity level (PAL) factor to estimate TDEE. The five standard factors are listed below.
Loss Rate
Your chosen weekly rate (0.5 to 2 lb/week). The calculator converts this to a daily deficit: rate × 500 calories.
Activity Multipliers
| Activity Level | Multiplier |
|---|---|
| Sedentary (desk job, little exercise) | 1.2 |
| Lightly active (1–3 days/week) | 1.375 |
| Moderately active (3–5 days/week) | 1.55 |
| Very active (6–7 days/week) | 1.725 |
| Extra active (physical job + training) | 1.9 |
Source: Mifflin-St Jeor (1990); PAL factors per Harris-Benedict convention and USDA Dietary Guidelines.
Worked Example: 30-Year-Old Woman, 165 lb, 65 in, Moderate Activity
Here is the full calculation from inputs to weight-loss calorie target, using a 1 lb/week goal.
Step 1 — Convert to metric:
Weight: 165 lb × 0.4536 = 74.8 kg
Height: 65 in × 2.54 = 165.1 cm
Step 2 — Mifflin-St Jeor BMR (women):
BMR = 10 × 74.8 + 6.25 × 165.1 − 5 × 30 − 161
BMR = 748 + 1,032 − 150 − 161 = 1,469 cal/day
Step 3 — Multiply by activity factor (moderate = 1.55):
TDEE = 1,469 × 1.55 = 2,277 cal/day
Step 4 — Subtract deficit (1 lb/week = 500 cal/day):
Target = 2,277 − 500 = 1,777 cal/day
Result: Eat 1,777 calories/day to lose ~1 lb/week
Source: Mifflin-St Jeor equation (1990); 1 lb fat ≈ 3,500 kcal.
Protein During a Deficit: Preserving Muscle
When you eat in a deficit, your body burns both fat and muscle for energy. Without enough protein and resistance training, a significant portion of weight lost can be muscle, which lowers your metabolic rate and makes weight regain more likely.
- Target 1.6 to 2.2 g of protein per kg of body weight during a deficit (per the International Society of Sports Nutrition).
- Spread protein across 3 to 4 meals (20 to 40 g each) to maximize muscle protein synthesis.
- Resistance train 2 to 4 times per week to signal your body to keep muscle.
- Don't crash-diet: deficits above 1,000 calories per day sharply increase muscle loss.
For our 74.8 kg example, that means 120 to 165 g of protein per day. Use the Protein Calculator to find your exact target.
Plateau Troubleshooting: Why the Scale Stopped Moving
Weight loss is rarely linear. Plateaus happen for predictable reasons. Here is how to diagnose and fix them:
- Re-check your intake: Portion creep is the number one cause. Weigh and log everything for one week.
- Recalculate TDEE: A lighter body burns fewer calories. Every 10 lb lost, recalculate with your new weight.
- Account for water: Stress, sodium, hormones, and sleep can mask 2 to 4 lb of fat loss with water retention. Give it 1 to 2 weeks.
- Increase non-exercise activity: Walking, standing, and fidgeting (NEAT) can add 100 to 300 calories per day to your TDEE.
- Consider a diet break: Eating at maintenance for 1 to 2 weeks can restore adherence and reverse metabolic adaptation.
If the plateau lasts more than 3 weeks despite accurate tracking, reduce your target by 100 to 200 calories or add 30 minutes of daily walking.
Weight Loss Calorie Calculator FAQs
Disclaimer: This weight loss calorie calculator provides estimates for educational purposes only and is not medical advice. Calorie needs vary by individual. The Mifflin-St Jeor equation has a standard error of about plus or minus 10 percent. Consult a healthcare professional before starting any diet, especially if you have a medical condition, are pregnant, or take medication.