Calorie Deficit Calculator for Fat Loss
Pick a realistic weekly fat loss rate and see the daily calorie target that gets you there without wrecking your training.
Daily calories for your deficit
- TDEE
- 2,763 kcal
- Daily deficit
- 500 kcal
- Weekly deficit
- 3,500 kcal
- 12-week loss
- 12.0 lb
Worked examples
How a calorie deficit is calculated
A calorie deficit is simply eating fewer calories than your body burns. The math:
1 lb of body fat ≈ 3,500 kcal1 kg of body fat ≈ 7,700 kcalDaily deficit = weekly loss × kcal per unit ÷ 7
So to lose 1 lb per week you need a deficit of 500 kcal per day. To lose 0.5 kg per week you need about 550 kcal per day. This calculator subtracts that deficit from your TDEE (computed from Mifflin-St Jeor BMR × activity multiplier) and shows what to eat.
How to use your deficit
Pick the smallest deficit that still produces visible progress on a 4-week average. Most people do best at 0.5–1% of bodyweight lost per week. That looks like:
- 150 lb / 68 kg adult → 300-500 kcal/day deficit
- 200 lb / 90 kg adult → 500-700 kcal/day deficit
- 250 lb / 113 kg adult → 700-900 kcal/day deficit
Larger humans can run larger deficits without trashing performance because they have more total body energy to draw on. The leaner you get, the more conservative you need to be.
Worked examples
Example 1. A 32-year-old woman, 168 cm, 70 kg, lightly active. TDEE ≈ 2,050 kcal. Goal: 1 lb/week. Daily deficit 500 kcal → eat 1,550 kcal/day. Realistic 12-week loss: 10-12 lb.
Example 2. A 38-year-old man, 183 cm, 95 kg, moderately active. TDEE ≈ 3,030 kcal. Goal: 1.5 lb/week. Daily deficit 750 kcal → eat 2,280 kcal/day. Realistic 12-week loss: 15-18 lb.
Example 3. A 45-year-old man, 180 cm, 110 kg, sedentary. TDEE ≈ 2,580 kcal. Goal: 1 kg/week. Daily deficit 1,100 kcal → eat 1,480 kcal/day. Aggressive but appropriate at higher bodyweights; reassess every 4 weeks and ease into a milder deficit as he leans out.
Common mistakes
- Picking the biggest deficit possible. You'll lose muscle, sleep, mood and lifts.
- Going by the daily scale. Use a 7-day average; expect plateaus of 2-3 weeks.
- Not tracking weekend meals. One restaurant night can erase three days of deficit.
- Confusing water drop with fat loss. The first 5-8 lb is mostly water and gut content.
- Never taking a break. A 2-week maintenance break every couple of months saves the diet.
FAQ
How big should my calorie deficit be?+
Aim for 0.5-1% of bodyweight lost per week. For most people that's a 300-500 kcal/day deficit. Going lower (more aggressive) accelerates muscle loss, hunger and adherence problems without speeding fat loss meaningfully.
Will 500 calories below TDEE always equal 1 lb lost per week?+
Roughly, on average, in the first few weeks. Over time, metabolism adapts a little and weight loss slows. Recalculate as you drop weight.
Can I create a deficit with exercise only?+
Possible but hard. Most people compensate with extra food and less spontaneous movement. Mix: most deficit from diet, a little from added activity.
Why isn't the scale moving despite a deficit?+
Usually water, especially in the first two weeks of a new program, after hard sessions, or around menstrual cycles. Look at four-week averages, not single days.
Is 1,200 calories safe?+
For very small or short people, sometimes. For most adults it's too aggressive and unsustainable. If your calculated target is under 1,500 kcal, slow down or add steps instead of cutting more.
Should I take diet breaks?+
Yes. Two weeks at maintenance every 6-12 weeks restores adherence, sleep and training quality without losing meaningful progress.
Related calculators
- TDEE CalculatorEstimate the calories you burn each day from your basal metabolic rate plus activity. Use the result as the starting line for cutting, bulking, or maintaining.
- Macro CalculatorTurn a calorie target into clear protein, carb, and fat grams. Pick a goal and we handle the math, including a sensible protein floor.
- BMR CalculatorFind the calories your body burns at complete rest using the Mifflin-St Jeor equation, the modern gold standard for BMR estimation.
- Protein Intake CalculatorGet a daily protein target in grams based on bodyweight, activity level, and whether you're cutting, maintaining, or building muscle.
- Body Fat CalculatorEstimate body fat percentage with the US Navy tape method. All you need is a soft tape measure and one minute.
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- Reverse Dieting CalculatorPlan a gradual week-by-week calorie increase after a cut, easing from your current intake back up toward maintenance while limiting fat regain.
- Weight Loss Timeline CalculatorSee how long it takes to reach your goal weight at a given calorie deficit, with a week-by-week curve and an estimated goal date.
- Calories Burned CalculatorEstimate the calories you burn for an activity and duration, based on your bodyweight and the activity's intensity.
- Heart Rate Zone CalculatorFind your max heart rate and five personalized training zones using the Karvonen method, so you train at the right intensity for your goal.
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Related guides
- How to Calculate Your Macros for Fat Loss (Complete Guide)A complete, no-fluff walkthrough for setting calories and macros that actually produce fat loss without trashing performance.
- How Many Calories Should I Eat to Lose Weight?A practical answer with the math, the trade-offs of aggressive vs slow deficits, and the calories most people actually need.
- What Is a Refeed Day? When and How to Use ThemWhat a refeed day actually is, who benefits, and the exact way to structure one without derailing your diet.