Note: This calculator is for general adults, not for pregnancy dieting. If you are pregnant, please follow your doctor’s advice.
Calorie Deficit Calculator
Find your maintenance calories, a safe daily target, and a realistic date to reach your goal weight.
Daily macros for your target
| Protein | Fat | Carbs |
|---|---|---|
Diet only, or diet plus exercise?
| Plan | Eat (kcal) | Burn through exercise (kcal) |
|---|
Your projected progress
| Week | Weight | Maintenance | Deficit |
|---|
Maintenance calories fall as you lose weight, so your deficit shrinks. We recalculate every week, which is why the date is later than the old "3,500 kcal per pound" rule suggests.
How to use this calculator
- Pick your sex and enter your age. The calculator is for adults aged 18 and over.
- Enter your current weight and choose kg or lb. Add a goal weight if you want a finish date.
- Enter your height in cm, or switch to ft/in.
- Choose your activity level. If unsure, pick one level lower, because most people overestimate how active they are.
- Select a daily deficit. 500 kcal is the best starting point for most people. Type your own number if you prefer.
- Optional: add your body fat % for a more accurate BMR, and say if you lift weights to raise your protein target.
- Press Calculate my deficit. You will see your BMR, maintenance calories, daily target, weekly loss, macros, a diet-vs-exercise split and a week-by-week projection.
- Weigh yourself weekly. If your weight has not moved for 3 to 4 weeks, recalculate with your new weight.
This tool gives estimates for healthy adults. It is not medical advice. Speak to a doctor first if you are pregnant, breastfeeding, under 18, diabetic, have a medical condition, or take regular medication.
Find Your Safe Daily Calories for Weight Loss
A calorie deficit means eating fewer calories than your body burns in a day. Your body covers the gap by using stored energy, mostly body fat, and that is how weight loss happens. Our calorie deficit calculator works out your maintenance calories, subtracts a deficit you choose, and gives you one daily calorie target, your weekly weight loss, your macros and a realistic goal date.
Unlike many basic tools, it does not stop at a single number. It shows how your result was built, protects you from unsafe targets, and recalculates your progress week by week as your body gets lighter.
Quick Answer: How Many Calories Should You Cut?
For most adults, a deficit of 300 to 500 calories per day is the best starting point. It leads to roughly 0.25 to 0.5 kg (0.5 to 1 lb) of weight loss per week, and it is much easier to stick to than a crash diet. Larger deficits are possible for people with more weight to lose, but they raise the risk of muscle loss, tiredness and rebound weight gain.
What Is a Calorie Deficit?
A calorie deficit happens when calories in are lower than calories out.
Calorie deficit = Calories burned (TDEE) − Calories eaten
Calories burned each day come from four sources:
| Source | What it means | Share of daily burn |
|---|---|---|
| BMR | Energy for breathing, heartbeat and organs at rest | 60% to 70% |
| NEAT | Walking, chores, fidgeting, standing | 15% to 30% |
| Exercise | Planned workouts | 5% to 10% |
| TEF | Energy used to digest food | About 10% |
Add them up and you get your TDEE (Total Daily Energy Expenditure), also called maintenance calories. Eat at TDEE and your weight stays stable. Eat below it and you lose weight.
How Does This Calculator Work?
- BMR. It uses the Mifflin-St Jeor equation, which is widely regarded as one of the most accurate for healthy adults. If you enter body fat %, it switches to the Katch-McArdle formula, which is based on lean mass.
- TDEE. Your BMR is multiplied by your activity level (1.2 for sedentary up to 1.9 for extra active).
- Deficit. It subtracts the deficit you chose (250, 500, 750, 1,000 or your own number).
- Safety checks. The deficit is capped at 25% of maintenance or 1% of body weight per week, whichever is smaller. The target never goes below 1,200 kcal for women or 1,500 kcal for men. If we change your number, we tell you why.
- Projection. Weekly loss uses about 7,700 kcal per kg of body weight, and maintenance is recalculated every week as your weight drops.
Calorie Deficit Formula With Example
Example: a 35-year-old woman, 165 cm, 86 kg, lightly active.
| Step | Calculation | Result |
|---|---|---|
| BMR (Mifflin-St Jeor) | 10 × 86 + 6.25 × 165 − 5 × 35 − 161 | 1,555 kcal |
| TDEE | 1,555 × 1.375 | 2,138 kcal |
| Deficit | 500 kcal | −500 |
| Daily target | 2,138 − 500 | 1,638 kcal |
| Weekly loss | 500 × 7 ÷ 7,700 | About 0.45 kg |
Why the Old “3,500 Calorie Rule” Is Misleading
Many calculators say 3,500 calories (about 7,700 kcal per kg) equals one pound of fat lost, and then multiply it by your deficit. Research by NIH scientists Kevin Hall and colleagues shows this rule overestimates real loss, because your metabolism slows as you get lighter. The NIH Body Weight Planner was built to correct for this.
Our calculator tackles the same problem in a simple way. Each week it lowers your estimated maintenance calories to match your new weight, so you see a longer, more realistic timeline instead of a perfect straight line.
Calorie Deficit Chart: What Each Deficit Gives You
| Daily deficit | Weekly loss (approx.) | Monthly loss (approx.) | Best for | Difficulty |
|---|---|---|---|---|
| 250 kcal | 0.23 kg | 1 kg | Beginners, lean people, last few kilos | Very easy |
| 500 kcal | 0.45 kg | 2 kg | Most adults (recommended) | Moderate |
| 750 kcal | 0.68 kg | 3 kg | Higher body weight, short phases | Hard |
| 1,000 kcal | 0.9 kg | 4 kg | Obesity, ideally under medical care | Very hard |
What Is a Safe Calorie Deficit?
- Aim for 0.5% to 1% of body weight per week. Faster loss usually costs muscle.
- Do not eat below 1,200 kcal (women) or 1,500 kcal (men) without medical supervision.
- Keep protein high. It protects muscle and keeps you full.
- Take diet breaks. After 8 to 12 weeks, eating at maintenance for 1 to 2 weeks can help adherence.
- Avoid deficits if you are pregnant, breastfeeding, under 18 or have an eating disorder history. Speak to a doctor first.
Daily Calorie Targets by Weight Maintenance vs 500 Deficit
Approximate values for adults of average height, lightly active.
| Body weight | Women: maintenance | Women: 500 deficit | Men: maintenance | Men: 500 deficit |
|---|---|---|---|---|
| 60 kg | 1,850 | 1,500 | 2,200 | 1,700 |
| 70 kg | 1,950 | 1,500 | 2,350 | 1,850 |
| 80 kg | 2,100 | 1,600 | 2,500 | 2,000 |
| 90 kg | 2,250 | 1,750 | 2,650 | 2,150 |
| 100 kg | 2,400 | 1,900 | 2,800 | 2,300 |
Use the calculator above for your exact numbers. These are only reference points.
Macros in a Calorie Deficit
Where your calories come from matters as much as how many you eat.
| Macro | Target | Why it matters |
|---|---|---|
| Protein | 1.6 to 2.0 g per kg (higher if you lift) | Preserves muscle, increases fullness |
| Fat | About 25% to 30% of calories | Hormones and vitamin absorption |
| Carbs | The remaining calories | Training energy and mood |
| Fibre | 14 g per 1,000 kcal | Fullness and gut health |
Need a more detailed breakdown? Try our Protein Intake Calculator and Macro Calculator.
Diet, Exercise or Both?
You can create the same deficit in different ways:
| Approach | Example (500 kcal deficit) |
|---|---|
| Diet only | Eat 500 kcal less than maintenance |
| Mixed | Eat 375 less, burn 125 more through walking |
| Half and half | Eat 250 less, burn 250 more through exercise |
A mixed approach is usually the most sustainable. Walking, strength training and daily movement also protect muscle and improve heart health.
Sample Calorie Deficit Food Swaps
| Instead of | Try | Calories saved (approx.) |
|---|---|---|
| 2 fried parathas | 2 plain rotis | 150 to 200 |
| Sugary tea, 3 cups a day | Tea with less or no sugar | 90 to 120 |
| Cold drink (330 ml) | Sparkling water with lemon | 140 |
| Fried snacks (samosa, pakora) | Roasted chana or fruit | 150 to 250 |
| Large serving of white rice | Smaller serving plus extra dal and vegetables | 100 to 200 |
| Packaged juice | Whole fruit | 80 to 120 |
Why Am I Not Losing Weight in a Calorie Deficit?
- Underestimating intake. Oil, sauces, snacks and weekend meals add up. Weigh food for two weeks.
- Overestimating activity. Pick a lower activity level if unsure.
- Water retention. Salt, hormones, stress and new workouts can hide fat loss for days.
- Too short a timeframe. Judge progress using a 2 to 3 week average, not daily weight.
- Poor sleep. Short sleep increases hunger and cravings.
- Your weight has changed. Recalculate every 4 to 5 kg lost.
- Medical causes. Thyroid problems, PCOS and some medications affect weight. See a doctor if progress stalls for months.
Common Mistakes to Avoid
- Cutting calories too aggressively and burning out
- Eating too little protein
- Skipping strength training
- Relying on exercise calorie estimates from watches, which are often too high
- Weighing yourself daily and panicking over normal fluctuations
- Comparing your timeline with someone else’s
Who Should Not Use a Calorie Deficit Without Medical Advice?
Pregnant or breastfeeding women, people under 18, people with diabetes or on insulin, people with kidney or heart disease, anyone with a history of eating disorders, and people with a low BMI. Check your BMI with our BMI Calculator first.
Related Calculators
- BMR and TDEE Calculator
- Daily Calorie Calculator
- Weight Loss Goal Date Calculator
- Protein Intake Calculator
- Water Intake Calculator
- Body Fat Percentage Calculator
Frequently Asked Questions
How do I calculate my calorie deficit?
Find your TDEE using your age, sex, height, weight and activity level, then subtract the calories you plan to eat. The difference is your deficit. The calculator above does this automatically.
Is a 500 calorie deficit good?
Yes, for most adults. It usually gives about 0.45 kg of loss per week and is realistic to maintain without extreme hunger.
How many calories should I eat to lose weight?
It depends on your body and activity. A common range is 1,200 to 1,500 kcal for smaller, less active women and 1,500 to 2,000 kcal for men, but your own number should come from your TDEE minus a safe deficit.
Can I lose weight without a calorie deficit?
No. Weight loss needs an energy deficit. Food quality, sleep and exercise help you create and maintain it, but they do not replace it.
How fast can I lose weight in a calorie deficit?
A safe pace is 0.5% to 1% of your body weight per week. People with obesity may lose a little faster at first, mostly because of water loss.
Is a 1,000 calorie deficit safe?
It can be unsafe for many people. It raises the risk of muscle loss, nutrient gaps, gallstones and fatigue. Use it only for short periods and ideally with medical advice.
How long can I stay in a calorie deficit?
Most people can stay in a moderate deficit for 8 to 16 weeks, then take a maintenance break before continuing.
Does the calculator work for men and women?
Yes. It uses different constants for each sex and sets different minimum calories (1,200 for women, 1,500 for men).
Should I eat back exercise calories?
If you use a moderate deficit and your activity level already includes exercise, there is no need to eat them back. Trackers often overestimate burned calories.
How often should I recalculate?
Every 4 to 5 kg lost, or whenever your activity level changes.
Is this calculator accurate?
It gives a well-supported estimate, not a measurement. Real calorie needs vary by about 10% to 15% between people. Track your weight for 2 to 3 weeks and adjust by 100 to 150 kcal if needed.
Final Thoughts
A calorie deficit is the one non-negotiable rule of fat loss, but the best deficit is a small, steady one you can keep. Use the calculator, aim for high protein, move daily, sleep well, and review your numbers every few weeks.