Calorie Deficit Calculator – How Many Calories to Cut to Lose Weight?
Find out exactly how large a calorie deficit you need to reach your weight loss goals. Our calorie deficit calculator helps you lose weight safely and sustainably.
Weight loss comes down to one thing: calorie deficit. Burn more than you eat, and your body taps into stored fat for energy. The rule of thumb is that 1 pound of body fat equals about 3,500 calories.
Create a 500-calorie daily deficit and you'll lose roughly 1 pound per week. Double that to 1,000 calories and you're looking at 2 pounds weekly. Sounds simple. And it is – until hunger, cravings, and life get in the way.
Calorie Deficit Formula
Daily Deficit = (Weight to Lose × 3,500) ÷ (Weeks × 7)
Example: 20 lbs in 10 weeks = (20 × 3,500) ÷ 70 = 1,000 calories/day deficit
| Deficit Size | Weekly Loss | Sustainability | Best For |
|---|---|---|---|
| 250 cal/day | 0.5 lb | Very Easy | Long-term maintenance, minimal hunger |
| 500 cal/day | 1 lb | Easy | Most people, sustainable long-term |
| 750 cal/day | 1.5 lb | Moderate | Faster results, some hunger expected |
| 1,000 cal/day | 2 lb | Challenging | Short-term goals, requires discipline |
| 1,250+ cal/day | 2.5+ lb | Difficult | Not recommended without medical supervision |
General recommendation: 500-750 calorie deficit for most people. This produces steady loss without excessive hunger or metabolic slowdown.
Reduce calorie intake
Cut 250-500 calories through diet. Swap soda for water (-150 cal), skip the afternoon snack (-200 cal), reduce portion sizes (-150 cal). Small changes add up without feeling deprived.
Increase physical activity
Burn 250-500 calories through exercise. A 30-minute brisk walk burns ~150 cal. Add strength training to preserve muscle. NEAT (non-exercise movement) matters too – take the stairs, park farther away.
Combine both approaches
The most sustainable approach: eat 250-300 calories less AND burn 250-300 calories more. This creates a 500-600 calorie deficit without extreme dieting or excessive exercise.
Is the 3,500 calories per pound rule accurate?
It's a useful approximation but not perfect. Research shows actual weight loss is often 20-30% slower than predicted, especially over longer periods. Your body adapts – metabolism slows as you lose weight. Use 3,500 as a starting point, then adjust based on real results.
Can I lose weight with just diet, no exercise?
Yes. Weight loss is primarily about calories in vs calories out. Diet has a bigger impact than exercise for most people. That said, exercise preserves muscle during weight loss, improves health markers, and helps maintain loss long-term.
Why isn't the scale moving despite my deficit?
Common reasons: water retention (especially when starting exercise or changing diet), underestimating intake (people typically undercount by 30-50%), or your actual TDEE is lower than calculated. Give it 2-3 weeks before adjusting.
How do I track calories accurately?
Use a food scale, not measuring cups. Log everything – condiments, cooking oil, bites and sips add up. Read labels carefully. Restaurant portions are often 2-3× standard servings. Track for at least 2 weeks to establish baseline accuracy.
Should I adjust my deficit as I lose weight?
Yes. As you lose weight, your TDEE drops – smaller bodies need fewer calories. Recalculate your deficit every 10-15 lbs lost. Also, metabolic adaptation can reduce TDEE by an extra 5-15% beyond what weight loss alone predicts.
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