Calorie Deficit Calculator
To lose 1 lb per week, create a 500 kcal/day deficit (1 lb fat ≈ 3,500 kcal). First calculate BMR using Mifflin-St Jeor: (10 × kg) + (6.25 × cm) − (5 × age) ± 5. Multiply by activity factor (1.2–1.9) to get TDEE (maintenance calories). Subtract your deficit from TDEE for your daily target. Minimum 1,200 kcal/day recommended for women, 1,500 for men.
Calculate your daily calorie target to lose weight at a specific rate. Uses the Mifflin-St Jeor BMR formula plus your activity level (TDEE) to find your maintenance calories, then subtracts your chosen deficit. Shows daily calorie goal, expected weekly weight loss, and macro breakdown.
Personal Details
Activity Level
Weight Loss Goal
Your Results
Macros Guideline
Suggested macros for 1,458 kcal/day:
How to Use
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Enter your personal details
Select your sex, enter your age, and enter your current weight (lbs or kg) and height (feet/inches or cm). These are used to calculate your Basal Metabolic Rate (BMR) via the Mifflin-St Jeor formula.
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Select your activity level
Choose the activity level that best matches your typical week: sedentary (desk job), light (1-3 days/week), moderate (3-5 days/week), active (6-7 days/week), or very active. This multiplier converts BMR to TDEE (daily maintenance calories).
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Set your weight loss goal
Choose your target weekly weight loss: 0.5, 1, 1.5, or 2 lbs/week. Each extra 0.5 lbs/week requires an additional 250 kcal/day deficit. 1 lb/week (500 kcal/day deficit) is the most commonly recommended pace.
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Read your calorie target
See your BMR, TDEE (maintenance), daily calorie target, daily deficit, and expected weekly loss. The macros guideline shows a suggested protein/carb/fat split for your target calories.
Frequently Asked Questions
- How many calories should I cut to lose 1 pound per week?
- 1 pound of fat ≈ 3,500 kcal. To lose 1 lb/week, create a 500 kcal/day deficit (3,500 ÷ 7 = 500). This can come from eating less, exercising more, or a combination. For example, eat 250 fewer calories and burn 250 more through exercise daily. Most health guidelines recommend a deficit of 500–750 kcal/day for sustainable weight loss (0.5–1.5 lbs/week). Larger deficits increase the risk of muscle loss and metabolic adaptation.
- What is TDEE and how is it different from BMR?
- BMR (Basal Metabolic Rate) is the calories your body burns at complete rest — just to maintain vital functions (breathing, circulation, organ function). TDEE (Total Daily Energy Expenditure) is your BMR multiplied by an activity factor: sedentary = BMR × 1.2, light activity = × 1.375, moderate = × 1.55, active = × 1.725, very active = × 1.9. TDEE is your true maintenance calories — the amount you need to eat to maintain your current weight with your actual activity level.
- What is the Mifflin-St Jeor formula?
- The Mifflin-St Jeor equation (1990) is the most accurate BMR formula for most people: Men: BMR = (10 × kg) + (6.25 × cm) - (5 × age) + 5. Women: BMR = (10 × kg) + (6.25 × cm) - (5 × age) - 161. Example: 30-year-old woman, 70 kg, 165 cm: BMR = 700 + 1031.25 - 150 - 161 = 1,420 kcal/day. Studies show this formula has ~10% accuracy for non-obese individuals, making it more reliable than the older Harris-Benedict equation.
- Is a 1,000 kcal/day deficit safe?
- A 1,000 kcal/day deficit produces about 2 lbs/week of weight loss in theory, but most experts recommend not exceeding 750-1,000 kcal/day deficits because: (1) muscle is lost more rapidly at very large deficits, (2) metabolic adaptation (your body lowers TDEE to compensate), (3) nutritional deficiencies are more likely, and (4) hunger and adherence become harder to manage. Sustainable 0.5–1 lb/week is generally preferable to aggressive short-term restriction.
- Why is 1,200 kcal/day often cited as the minimum?
- 1,200 kcal/day is the traditional minimum for women (1,500 for men) cited by dietitians as the lower bound for getting sufficient micronutrients without supplementation. Below this threshold, it becomes difficult to meet protein, vitamin, and mineral needs from food alone. This threshold is a rough guideline, not a strict rule — very small individuals may have lower TDEE and safely eat slightly less, but deficits below this level should be medically supervised.
- How does the calorie deficit change as you lose weight?
- As you lose weight, your BMR decreases (less body mass to maintain), so your TDEE drops too. This means the same food intake produces a smaller deficit over time — a phenomenon called metabolic adaptation. This is why weight loss often plateaus after several weeks. Recalculate your calorie target every 5-10 lbs of weight lost to adjust for your new (lower) TDEE. Also re-evaluate your activity level if your exercise routine has changed.