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 to Lose (lbs)

Timeframe (weeks)

Understanding Calorie Deficits

The math behind weight loss

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

Safe Deficit Guidelines

How aggressive should you go?

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.

How to Create a Calorie Deficit

Practical strategies that work

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.

Frequently Asked Questions

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.

Other Free Tools

Search tools

Calorie Deficit Calculator – How Many Calories to Cut to Lose Weight?

Frequently Asked Questions

Other Free Tools

Activity Calorie Calculator

Daily Calorie Needs Calculator

Steps To Calories Calculator

Cycling Calorie Calculator

Swimming Calorie Calculator

Walking Calorie Calculator