ganak.appCalorie Deficit Calculator
Free calorie deficit calculator for weight loss. Enter your stats and goal weight to get your daily calorie target, deficit amount, and estimated timeline. Includes weight loss projection chart, macronutrient breakdown, 7-day calorie cycling plan, and multi-deficit comparison. Uses Mifflin-St Jeor and Katch-McArdle formulas.
Recommended for most people
10 kg to lose
500 kcal deficit from maintenance
Deficit Comparison
Compare different deficit levels and their timelines
| Deficit | Cal/day | kg/wk | Timeline |
|---|---|---|---|
Mild Deficit | 2,412 | 0.2 | ~10.2 months |
Moderate Deficit | 2,162 | 0.5 | ~5.1 months |
Aggressive Deficit | 1,912 | 0.7 | ~3.5 months |
Extreme Deficit | 1,662 | 0.9 | ~2.5 months |
Weight Loss Projection
Estimated weight over time at 500 kcal/day deficit
Daily Macronutrients
Optimized macro split for a weight loss deficit (30/25/45)
162g
Protein (30%)
60g
Fat (25%)
243g
Carbs (45%)
7-Day Calorie Cycling Plan
Zigzag your calories for better adherence. Weekly average: 2,162 kcal/day
Mon
2,162
Tue
1,838
Wed
2,486
Thu
2,162
Fri
1,838
Sat
2,486
Sun
2,162
What Your Deficit Looks Like
Your 500 kcal/day deficit equals skipping:
Chicken Nuggets (10 pc)
1.1xLarge Fries
1xPepperoni Pizza Slice
1.7xPotato Chips
3.3xEach item x count approximates your daily 500 kcal deficit
Understanding Your Numbers
Your BMR, TDEE, activity factor, and how far you are from your goal
BMR
1,718
Calories at rest
TDEE
2,662
Maintenance calories
Activity Factor
1.55x
BMR multiplier
Weight to Lose
10 kg
To reach goal
Formula Comparison
What is a Calorie Deficit?
The science behind eating less than you burn and why it leads to weight loss
A calorie deficit occurs when you consume fewer calories than your body burns in a day. This forces your body to use stored energy (primarily body fat) to make up the difference, resulting in weight loss over time.
For example, if your body burns 2,200 calories per day (your TDEE) and you eat 1,700 calories, you have a 500-calorie deficit. Over one week, this adds up to a 3,500-calorie deficit, which is roughly equivalent to losing about 0.45 kg (1 lb) of body fat.
How calorie deficit works:
- 1.Your body needs a certain number of calories to function (your TDEE)
- 2.When you eat less than your TDEE, your body taps into fat stores for energy
- 3.A consistent deficit over weeks and months leads to measurable weight loss
How This Calculator Works
A 3-step process: BMR, then TDEE, then your deficit target
Calculate your BMR (Basal Metabolic Rate)
Using the Mifflin-St Jeor equation, we calculate the calories your body burns at complete rest. This is the energy needed for basic functions like breathing, circulation, and cell production.
Men: BMR = (10 x weightkg) + (6.25 x heightcm) - (5 x age) + 5
Women: BMR = (10 x weightkg) + (6.25 x heightcm) - (5 x age) - 161
Calculate your TDEE (Total Daily Energy Expenditure)
Your BMR is multiplied by an activity factor (1.2 to 1.9) based on your exercise habits. This gives your maintenance calories — what you need to eat to stay at your current weight.
Apply your calorie deficit
We subtract your chosen deficit amount (250-1,000 kcal) from your TDEE to get your daily calorie target. This target is what you should aim to eat each day for weight loss.
BMR Formula Comparison
Mifflin-St Jeor vs Katch-McArdle — which one to use and when
| Formula | Best For | Requires |
|---|---|---|
| Mifflin-St Jeor | Most people (default) | Age, weight, height, gender |
| Katch-McArdle | Lean/athletic individuals | Weight, body fat % |
The Mifflin-St Jeor equation is the most widely recommended by nutrition professionals. It has been shown to be within 10% of measured values for most individuals.
If you know your body fat percentage, the Katch-McArdle formula can be more accurate, especially for people with higher or lower than average muscle mass. Select it under Advanced Options.
Common Mistakes to Avoid
Five pitfalls that stall weight loss and how to sidestep them
Cutting too many calories too fast
Extreme deficits (1,000+ kcal) cause muscle loss, metabolic slowdown, and are nearly impossible to sustain. Start with a moderate deficit of 500 kcal/day.
Not accounting for metabolic adaptation
As you lose weight, your body burns fewer calories. Recalculate your TDEE every 5-10 kg (10-20 lbs) lost to keep your deficit effective.
Overestimating activity level
When in doubt, select one level lower. People frequently overestimate how active they are, leading to a smaller actual deficit than planned.
Ignoring protein intake
During a calorie deficit, protein is critical for preserving muscle mass. Aim for 1.6-2.2g of protein per kg of body weight, even when cutting calories.
Expecting linear weight loss
Weight fluctuates daily due to water retention, sodium intake, and hormones. Focus on the weekly trend, not day-to-day changes.
Tips for a Successful Calorie Deficit
Practical habits that make your deficit sustainable and effective
Track your food
Even for a few weeks. Most people underestimate intake by 20-50%. Use a food scale for accuracy.
Prioritize protein
It keeps you full longer, preserves muscle, and has the highest thermic effect of food.
Try calorie cycling
Vary intake throughout the week — higher on workout days, lower on rest days. Use the 7-day plan above.
Weigh yourself consistently
Same time, same conditions (morning, after bathroom). Use weekly averages, not daily numbers.
Include resistance training
Lifting weights while in a deficit is the best way to preserve (or even gain) muscle mass.
Take diet breaks
Eat at maintenance for 1-2 weeks every 8-12 weeks to prevent metabolic adaptation and improve adherence.
Frequently Asked Questions
Common questions about calorie deficits, weight loss, and this calculator