Deficitly
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Calorie deficit calculator
A calorie deficit means eating fewer calories than you burn, so your body makes up the difference from stored fat. A deficit big enough to lose about 0.5% of your body weight a week is a pace most people can keep. For a 40-year-old woman of 70 kg (154 lb) and 165 cm at 8,000 steps a day, that's eating about 1,500 instead of her maintenance of 1,890: a deficit of 390 calories, and about 0.35 kg (0.8 lb) a week.
What is a calorie deficit?
It's the "calories out" side of CICO winning. Your body burns a certain number of calories each day: your maintenance, or TDEE. Eat less than that and the gap, the calorie deficit, comes from your energy stores, mostly fat. About 7,700 calories add up to 1 kg of body fat (3,500 per pound), so a steady deficit of 500 a day loses roughly 0.45 kg (1.0 lb) a week. Your maintenance comes from the maintenance calorie calculator.
How big should your calorie deficit be?
| Deficit | Per week | At 60 kg | At 80 kg | At 100 kg |
|---|---|---|---|---|
| 250 kcal | 0.23 kg0.5 lb | 0.38% | 0.28% | 0.23% |
| 500 kcal | 0.45 kg1.0 lb | 0.76% | 0.57% | 0.45% |
| 750 kcal | 0.68 kg1.5 lb | 1.14% | 0.85% | 0.68% |
| 1,000 kcal | 0.91 kg2.0 lb | 1.52% | 1.14% | 0.91% |
The popular "500 calories a day" is a big deficit for a small person and a small one for a big person: it's 0.76% of body weight a week at 60 kg but only 0.45% at 100 kg. More on the classic number in 500-calorie deficit: how much weight will you lose?. That's why the calculator sizes the deficit to your weight: 0.5% a week is steady, up to 1% is possible, and faster loss costs more muscle and is harder to keep up. More in how many calories should I eat to lose weight.
Calorie deficit examples
| Person | Burn | Eat | Deficit | Per week |
|---|---|---|---|---|
| Woman, 60 kg 132 lb | 1,730 | 1,400 | 330 | 0.30 kg0.7 lb |
| Woman, 70 kg 154 lb | 1,890 | 1,500 | 390 | 0.35 kg0.8 lb |
| Woman, 85 kg 187 lb | 2,120 | 1,650 | 470 | 0.42 kg0.9 lb |
| Man, 75 kg 165 lb | 2,280 | 1,870 | 410 | 0.38 kg0.8 lb |
| Man, 90 kg 198 lb | 2,520 | 2,020 | 500 | 0.45 kg1.0 lb |
| Man, 110 kg 243 lb | 2,830 | 2,220 | 610 | 0.55 kg1.2 lb |
The minimum: 1,200 or 1,500 calories
However fast you want to go, the calculator never suggests less than 1,200 calories a day for women or 1,500 for men. Below that it gets hard to eat enough protein, vitamins and minerals, and diets are normally done with a doctor's support. If a pace would need less, it's capped and marked. See is 1,200 calories a day safe?
How to create a calorie deficit
You can eat less, move more, or both. Eating less does most of the work for most people: a 500-calorie deficit from walking alone would take about 19,000 extra steps a day at 75 kg (165 lb). But steps keep your burn up while you diet, so a mix works well: a modest cut in food plus a few thousand more steps. Keep protein high so the weight you lose is mostly fat; the macro calculator splits your target into protein, carbs and fat (new to macros? see what are macros?). See also how many steps a day to lose weight.
How long will it take?
| Lose | Gentle0.25%/week | Steady0.5%/week | Faster0.75%/week |
|---|---|---|---|
| 5 kg11 lb | 25 weeks | 13 weeks | 9 weeks |
| 10 kg22 lb | 50 weeks | 25 weeks | 17 weeks |
| 20 kg44 lb | 100 weeks | 50 weeks | 34 weeks |
More starting weights and paces, in kg and lb: how long it takes to lose 10 kg.
In a calorie deficit but not losing weight?
Usually one of three things. Water: the scale can hide fat loss for a week or two, especially around your period or after salty meals; look at the trend over 3–4 weeks. Counting: most people underestimate what they eat by 10–30%. Your burn has dropped: after losing weight your maintenance is lower, so the same intake is a smaller deficit (see weight-loss plateau). Work out your real number from your own results with the real TDEE calculator, and see all seven common reasons in calorie deficit but not losing weight.