A calorie deficit of 250 to 500 calories below your maintenance level is the usual starting point, and it leads to roughly 0.5 to 1 pound (0.25 to 0.5 kg) of weight loss a week. Your maintenance level is your TDEE, the calories you burn in a day. Bigger deficits lose weight faster but are harder to keep up and can cost muscle.
Daily calories to lose weight = TDEE − deficit. If your TDEE is 2,200, eating about 1,700 calories gives a 500 calorie deficit, or about 1 lb a week. Do not go below 1,200 calories (women) or 1,500 (men) without medical supervision. Find your TDEE with the calorie calculator.
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How a calorie deficit works
Your body burns energy all day. That total is your TDEE (total daily energy expenditure): resting energy (BMR) plus everything you do. If you eat less than your TDEE, your body makes up the difference from stored energy, mainly body fat. That gap is the deficit.
One pound of body fat holds roughly 3,500 calories (about 7,700 per kilogram). So a 500 calorie deficit every day adds up to 3,500 a week, or about one pound.
Deficit size and weekly weight loss
This table uses a TDEE of 2,200 calories as an example. Replace it with your own number.
| Daily deficit | Daily calories | Weekly loss | Time to lose 10 lb (4.5 kg) | Time to lose 20 lb (9 kg) |
|---|---|---|---|---|
| 250 | 1,950 | 0.5 lb (0.23 kg) | 20 weeks | 40 weeks |
| 500 | 1,700 | 1 lb (0.45 kg) | 10 weeks | 20 weeks |
| 750 | 1,450 | 1.5 lb (0.68 kg) | 6.7 weeks | 13 weeks |
| 1,000 | 1,200 | 2 lb (0.91 kg) | 5 weeks | 10 weeks |
Health bodies commonly describe about 1 to 2 pounds a week as a steady, sustainable pace. Smaller people have less room to cut, so a 1,000 calorie deficit that works for a heavier person can push a smaller person below a safe intake. Another way to size it is a percentage: many people use 10 to 25 percent of TDEE. For 2,200 calories, that is 220 to 550.
Two worked examples
Both use the Mifflin-St Jeor equation for BMR, then multiply by an activity factor to get TDEE.
Example 1: a 30-year-old woman, 165 cm, 65 kg, lightly active
- BMR = 10 × 65 + 6.25 × 165 − 5 × 30 − 161 = 1,370 (rounded)
- TDEE = 1,370 × 1.375 = 1,884
- 250 calorie deficit: 1,634 calories a day, about 0.5 lb a week
- 500 calorie deficit: 1,384 calories a day, about 1 lb a week, still above 1,200
Example 2: a 40-year-old man, 178 cm, 100 kg, lightly active
- BMR = 10 × 100 + 6.25 × 178 − 5 × 40 + 5 = 1,918 (rounded)
- TDEE = 1,918 × 1.375 = 2,637
- 500 calorie deficit: 2,137 calories a day, about 1 lb a week
- To lose 20 lb at that pace: about 20 weeks, though the number will drift as weight falls
Choose the activity factor honestly. The usual multipliers are 1.2 (little exercise), 1.375 (light), 1.55 (moderate), 1.725 (hard) and 1.9 (very hard). Overestimating it is the most common reason a plan seems to stop working. Different BMR formulas also give slightly different results, which the BMR formulas guide explains.
Why the 3,500 rule is only an estimate
The 3,500 calories per pound figure is a handy approximation, not an exact law. In real life:
- Your TDEE falls as you get lighter. A smaller body burns less, so the same intake gives a smaller deficit over time. Recalculate after every 10 pounds (about 4.5 kg) lost.
- Your body adapts. Energy use can drop a little more than weight alone predicts, and everyday movement often decreases without you noticing.
- Water shifts the scale. Salt, carbohydrate intake and hormones can move weight by a pound or more from day to day.
- Food labels and logging are imprecise. Even careful tracking is often off by 10 percent or more.
Treat the first estimate as a starting point. Track your weight for 2 to 4 weeks, then adjust by 100 to 200 calories if the trend is off.
The lowest sensible intake
Many guidelines treat 1,200 calories for women and 1,500 for men as the lowest intake to use without a doctor or dietitian. Going lower makes it harder to meet nutrient needs and raises the odds of fatigue, muscle loss and rebound eating. If your calculated target falls below these numbers, choose a smaller deficit or a longer timeline instead, as in Example 1 above.
Anyone who is pregnant or breastfeeding, under 18, has a history of disordered eating, or has a medical condition such as diabetes or heart disease should talk to a doctor or registered dietitian first. If food or weight feels stressful or out of control, ask for professional support. This guide gives estimates, not a treatment plan.
Cut food, move more, or both
You can make a deficit from eating less, moving more, or a mix. A mix is usually easier to sustain. For example, a 500 calorie deficit could be 300 from walking and 200 from small food changes.
| Source | Example | Approx. calories |
|---|---|---|
| Walking | 10,000 steps for a 70 kg person | 290 to 380 |
| Drinks | Swap one 20 oz sweetened soda for water | about 240 |
| Portions | Trim each of two meals by about 100 calories | 200 |
| Snacks | Skip one daily 250 calorie snack | 250 |
To see what your daily steps are worth, see the guide on how many steps a day you need.
Protecting muscle while you lose fat
When you eat less, you can lose some muscle along with fat. Two habits help limit that: keep your protein intake adequate and keep doing some resistance exercise. Many dietitians suggest more protein during weight loss than the basic minimum, often in the range of about 1.2 to 1.6 grams per kilogram of body weight, but your own needs depend on your health, so check with a professional if you are unsure. The macros calculator splits your calories into protein, carbohydrate and fat.
When weight loss stalls
- Wait two to three weeks. Scale weight is noisy, so judge by the weekly average, not a single day.
- Recheck your numbers. Update your weight in the calculator, because your TDEE is now lower.
- Audit your logging. Weekends, oils, drinks and bites often add several hundred calories.
- Add movement before cutting more food. An extra 1,000 to 2,000 steps a day is a gentler lever than a deeper cut.
- Plan a maintenance break. A week or two at maintenance can make a long diet easier to finish.
How to use the calorie calculator
Enter your details
Add age, sex, height, weight and an honest activity level.
Set a goal weight and timeline
The calculator shows the daily deficit and warns when a plan is too aggressive.
Review and adjust
Check your targets and macros, then update the numbers every 10 pounds you lose.
Frequently Asked Questions
Conclusion
Start with your TDEE, subtract 250 to 500 calories, stay above the 1,200 and 1,500 floors, and judge progress over 2 to 4 weeks before changing anything. Update your numbers as you lose weight, and use the calorie calculator to set a target that matches your goal and timeline.
This guide gives general estimates and is not medical or dietary advice. Individual calorie needs vary. Consult a doctor or registered dietitian before starting a weight-loss plan, especially if you have a medical condition.