Daily Calorie Deficit Calculator
Use this tool to estimate your maintenance calories (TDEE) and a practical calorie target for fat loss.
Most people do well between 10% and 25%. Larger deficits are harder to sustain.
What is a calorie deficit?
A calorie deficit means eating fewer calories than your body uses in a day. When this happens consistently, your body uses stored energy (mostly body fat) to cover the gap. That is the foundation of fat loss.
Your body burns calories through:
- Basal metabolic rate (BMR): energy needed for vital functions at rest
- Activity: workouts, walking, movement throughout the day
- Thermic effect of food: energy used to digest and process food
This calculator estimates your total daily energy expenditure (TDEE), then applies a deficit percentage to generate a practical daily calorie target.
How this deficit calorie calculator works
1) Estimate BMR
We use the Mifflin-St Jeor equation, one of the most widely used formulas for estimating resting calorie needs from age, sex, height, and weight.
2) Estimate TDEE
Your BMR is multiplied by an activity factor based on how active your week typically looks. This gives an estimate of maintenance calories.
3) Apply your target deficit
If you choose a 20% deficit, your intake goal becomes approximately 80% of maintenance. The tool also estimates expected weekly weight change from that daily deficit.
How big should your calorie deficit be?
There is no one-size-fits-all answer, but these ranges are common:
- 10-15% deficit: easier adherence, slower fat loss, often better for lean individuals
- 15-25% deficit: balanced rate for most people
- 25-35% deficit: faster short-term loss, higher fatigue/hunger risk
In practice, the best deficit is the one you can maintain for months while preserving performance, muscle, sleep quality, and mood.
Tips to make your deficit sustainable
Prioritize protein
Protein helps preserve lean mass and improves satiety. A practical target is often around 1.6-2.2 g/kg body weight per day, adjusted for your needs and training status.
Lift weights or do resistance training
Resistance training signals your body to retain muscle while dieting. Even 2-4 quality sessions per week makes a major difference.
Use high-volume foods
Vegetables, fruits, potatoes, legumes, and lean proteins can help you feel fuller with fewer calories.
Track trends, not single days
Body weight fluctuates due to water, sodium, stress, and digestion. Use a 7-day average to evaluate progress.
Why your progress may stall
- Portion drift and under-tracking over time
- Lower daily movement (NEAT) as dieting fatigue builds
- Sleep loss and stress, which can increase hunger and reduce recovery
- An activity level estimate that is too high
If progress stalls for 2-3 weeks, reduce calories slightly (for example 100-150 kcal/day), increase steps, or tighten tracking accuracy before making big changes.
Example
Suppose your maintenance is 2,400 kcal/day. A 20% deficit is 480 kcal/day, giving a target intake of about 1,920 kcal/day. Over a week, that could produce around 0.4-0.5 kg (0.9-1.1 lb) of weight loss, though real-world results vary.
Final notes
This calculator gives a data-informed starting point, not a perfect prediction. Your metabolism and activity change over time, so adjust based on outcomes every few weeks. Consistency, sleep, training, protein, and stress management are just as important as calorie math.