Calorie Deficit Calculator
Tell us where you are and where you want to be. We’ll show the daily calories to get there, and flag it if the pace you picked is unrealistic.
Eat this many calories a day
2,000 cal/day
Maintenance 2,500 minus a deficit of 500
To lose
22 lb
Weekly rate
1.0 lb
Estimated finish
–
22 weeks
The timeline assumes a constant 3,500 calories per pound and a fixed maintenance level. Neither holds exactly. As you get lighter you burn less, so real progress slows toward the end. Recalculate every 10 to 15 lb.
How a calorie deficit works
A deficit means taking in less energy than you spend, so your body covers the shortfall from stored fat. Everything else you have read about, whether that is meal timing, fasting windows, low carb or low fat, only matters through its effect on that balance or on how easy the balance is to hold.
A pound of body fat stores roughly 3,500 calories, so a 500 calorie daily deficit predicts about a pound a week. That arithmetic is where every calculator starts, including this one, and it is worth knowing its limits. It treats your maintenance level as fixed when it actually falls as you get lighter. The number is a good starting point and a poor long-range forecast.
The other thing worth saying early: a deficit is a temporary tool, not a permanent way of eating. The people who keep weight off are the ones who spend time at maintenance afterward and learn what that looks like on a plate.
Deficit size and how fast it moves
| Daily deficit | Weekly loss | Time to lose 20 lb | How it feels |
|---|---|---|---|
| 250 cal | 0.5 lb | 40 weeks | Barely noticeable |
| 375 cal | 0.75 lb | 27 weeks | Easy to sustain |
| 500 cal | 1 lb | 20 weeks | The classic target. Manageable. |
| 750 cal | 1.5 lb | 13 weeks | Noticeably hungry by evening |
| 1,000 cal | 2 lb | 10 weeks | Hard. Only appropriate at higher body weights. |
A 1,000 calorie deficit is reasonable for someone at 280 lb and reckless for someone at 140. That is why percentage of body weight is the better guide, and why this calculator works in percentages rather than fixed numbers.
A safe weekly rate for your size
| Current weight | Steady (0.5%/week) | Faster (1%/week) |
|---|---|---|
| 140 lb | 0.7 lb | 1.4 lb |
| 160 lb | 0.8 lb | 1.6 lb |
| 180 lb | 0.9 lb | 1.8 lb |
| 200 lb | 1.0 lb | 2.0 lb |
| 250 lb | 1.2 lb | 2.5 lb |
| 300 lb | 1.5 lb | 3.0 lb |
The leaner you get, the closer you should sit to the lower column. With less fat available, a fast rate starts taking the difference from muscle.
Protecting muscle while you lose
Eat enough protein
0.7 to 1 g per pound of body weight. This single habit does more than anything else on this page. Get your target.
Keep lifting
Two or three sessions a week tell your body the muscle is still needed. Cardio alone sends no such signal.
Sleep
Short sleep shifts the composition of what you lose toward muscle, and makes hunger much harder to manage the next day.
Don’t rush
Very fast loss takes a bigger share from lean tissue. The scale moves either way. What it costs you differs.
Why the scale lies to you
Body weight swings 2 to 4 lb in a single day, and almost none of that is fat. Water moves for all sorts of reasons: a salty dinner, a hard leg session, a poor night of sleep, a stressful week, the point you are at in a menstrual cycle. Carbohydrate is stored with roughly 3 g of water per gram, so a high-carb weekend alone can add several pounds on the scale by Monday.
None of that is fat gain. It just happens to move faster and louder than fat loss does. Someone losing a genuine pound of fat a week is looking for a change of 0.14 lb per day, hidden inside noise ten times that size.
The fix is simple. Weigh every morning under the same conditions, then compare weekly averages instead of individual days. Two weeks of averages tells you the truth, and it will spare you the Wednesday morning where the number goes up and you conclude the whole thing is broken.
What to do when progress stalls
Wait three weeks before calling it a stall. Two flat weeks is normal variation, particularly for women across a cycle. Plenty of real progress gets abandoned at the two week mark.
Re-weigh your food for a week. Portion drift is the most common cause by a wide margin. Oil, nut butter, cheese and sauces are the usual suspects, and a tablespoon of olive oil is 120 calories.
Check your step count against a month ago. Daily movement quietly falls during a diet. Getting back to your old step count often restarts progress without touching your food.
Recalculate for your new weight. Down 15 lb, your maintenance is roughly 100 calories lower than when you started. The target that worked in January will not work in April.
Consider a diet break instead of a bigger cut. After several months, one or two weeks at maintenance often does more for the next phase than another 200 calories off would.
Foods that make a deficit easier
Hunger is the reason most diets end, so the practical skill is getting more food for the same calories. Protein and fiber do most of that work, and water content does the rest.
Filling for the calories
- Chicken breast, white fish, shrimp
- Eggs and egg whites
- Greek yogurt and cottage cheese
- Potatoes, which score highest of any food on satiety per calorie
- Beans, lentils and chickpeas
- Berries, apples, oranges
- Any non-starchy vegetable, in volume
Easy to overshoot on
- Cooking oils and butter, 100 to 120 calories a tablespoon
- Nuts and nut butter, calorie dense and easy to eat absently
- Soda, juice, sweetened coffee, alcohol
- Dressings, sauces and condiments
- Granola and trail mix, healthy sounding and extremely dense
- Anything eaten straight from the package
Nothing in the right-hand column is off limits. They just need measuring rather than pouring, because they are where an intended 500 calorie deficit turns into 150 without anyone noticing.