Calorie deficit explained: how to calculate yours
October 6, 2026 · 3 min read
A calorie deficit means taking in fewer calories than your body burns. Your body covers the gap from its stores, and over time you lose weight. Whatever diet you follow, this is the mechanism behind the result.
How to calculate your deficit
- Find what you burn. Estimate your total daily energy expenditure (TDEE) from your height, weight, age and activity. The formula and examples are in how many calories should I eat a day.
- Pick a deficit. Subtracting 300–500 calories is a sustainable starting point for most people.
- Use what is left as your target. If you burn 2,200 calories and choose a 500-calorie deficit, your daily target is 1,700.
How much deficit for how much weight?
A pound of body fat is roughly 3,500 calories (about 7,700 per kilogram). On that basis:
| Daily deficit | Weekly deficit | Estimated weekly loss |
|---|---|---|
| 250 calories | 1,750 | about 0.5 lb (0.25 kg) |
| 500 calories | 3,500 | about 1 lb (0.45 kg) |
| 750 calories | 5,250 | about 1.5 lb (0.7 kg) |
| 1,000 calories | 7,000 | about 2 lb (0.9 kg) |
Treat these as rough averages. The scale usually drops faster in the first weeks because of water, then slows. As you get lighter you also burn less, so the same intake becomes a smaller deficit over time.
What is a safe limit?
Losing 1–2 lb (0.5–1 kg) a week is generally considered reasonable. More aggressive deficits raise the odds of muscle loss, fatigue and giving up. Unless a health professional advises it, women are told not to go below 1,200 calories a day and men not below 1,500.
Keep protein up while calories come down
Enough protein during a deficit helps you hold on to muscle and stay full for longer. A commonly used range while losing weight is 1.2–1.6 g of protein per kilogram of body weight per day. For a 70 kg (154 lb) person that is 85–110 g.
5 common mistakes
- Not counting oils and sauces. A tablespoon of olive oil is about 120 calories. A "drizzle" on a salad can erase half your deficit.
- Forgetting drinks. Sweetened coffee, juice and alcohol add up quickly.
- Skipping weekends. Five days at a 500-calorie deficit is cancelled by two days at 1,250 over.
- Eyeballing portions. With rice, pasta and nuts, a guess is usually an underestimate.
- Overrating exercise burn. Watches and treadmills tend to read high. Do not eat all of it back.
How do you know you are in a deficit?
The only real test is the trend over a few weeks. Your weight can swing by a couple of pounds from day to day, so look at the weekly average. If the average has not moved in three weeks, either your logging has gaps or the target needs to come down by another 100–200 calories.
Make the tracking easy
The hard part of a deficit is logging every meal. In Cal Crew you take a photo of your plate, AI estimates the calories and macros, and you see what is left for the day as you go. Add friends to your crew and you compete on the same leaderboard. We wrote separately about why tracking with friends works.