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Calorie deficit calculator
How many calories to eat to lose weight at the pace you choose, and when you'll reach your goal weight.
To lose 0.5 kg a week: 550 kcal a day below your TDEE
Your calories at each pace
| Pace a week | Of body weight | Calories a day | Time to goal |
|---|---|---|---|
| 0.25 kg | 0.3% | 2,480 | 20 weeks |
| 0.5 kg | 0.6% | 2,210 | 10 weeks |
| 0.75 kg | 0.9% | 1,930 | 7 weeks |
| 1 kg | 1.3% | 1,660 | 5 weeks |
How your deficit is worked out
- Maintenance: your TDEE, from the Mifflin-St Jeor equation and your activity level (see the TDEE calculator). Eating this much keeps your weight steady.
- Deficit: a kilogram of body fat holds about 7,700 kcal (a pound about 3,500), so losing 0.5 kg a week takes about 550 kcal a day below maintenance.
- A floor: the target never goes below 1,500 kcal a day for men or 1,200 for women, the lowest Harvard Health advises without a doctor's supervision. If your pace needs less, the calculator holds you at the floor and shows the slower pace you'll get.
- Time to goal: the weight to lose divided by your weekly pace.
Treat the date as a best case. As you get lighter you burn less, so the same intake loses weight more slowly over time, and over months the 7,700 kcal rule predicts more loss than people see. Recalculate every 4 to 5 kg (about 10 lb) you lose.
How fast should you lose weight?
If you lift or run, aim for 0.5 to 1% of your body weight a week: slow enough to keep muscle and strength, fast enough to see progress. In a study of elite athletes, those losing about 0.7% of their body weight a week gained more lean mass and strength than those losing 1.4%.
For an 80 kg person that's 0.4 to 0.8 kg a week. If you're training for a race or a Hyrox, stay at the slow end. A big deficit makes hard sessions harder to recover from.
Making it work
- Keep protein high, around 2.2 g per kg of body weight, to hold on to muscle (protein calculator). The macro calculator splits your calories into protein, carbs and fat.
- Weigh yourself a few mornings a week and watch the weekly average. Single days swing with water and salt.
- If the average hasn't moved after two to three weeks, cut another 100 to 200 kcal a day or add activity.
- Eat more on your hardest training days and less on rest days. The weekly total is what counts.
Stay in your deficit without the spreadsheet
Elevus sets your calorie and macro targets from your body, your goal and your training days. Log meals from a photo, a barcode, a nutrition label or your voice.
Download on theApp StoreFree to download · iPhone
FAQ
How big should my calorie deficit be?
Big enough to lose 0.5 to 1% of your body weight a week. For most people that's about 300 to 800 kcal a day below maintenance.
How many calories should I eat to lose 1 kg a week?
About 1,100 kcal a day below your maintenance (7,700 kcal over 7 days). Under about 100 kg, that's faster than 1% of your body weight a week, so you'll lose muscle along with fat. 0.5 kg a week is easier to keep up.
Why has my weight loss slowed down?
A lighter body burns fewer calories, so the same intake makes a smaller deficit. Water and food also move the scale day to day. Recalculate with your new weight and judge by the weekly average, not single days.
What is the lowest number of calories I should eat?
Harvard Health advises not going below 1,200 kcal a day for women or 1,500 for men without a doctor's supervision. If you train hard your floor is higher: eating too little for your training hurts recovery, hormones and bone health.
References
- Mifflin MD, St Jeor ST, Hill LA, et al. A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition. 1990;51(2):241–247.
- Hall KD, Sacks G, Chandramohan D, et al. Quantification of the effect of energy imbalance on bodyweight. The Lancet. 2011;378(9793):826–837.
- Helms ER, Aragon AA, Fitschen PJ. Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. Journal of the International Society of Sports Nutrition. 2014;11:20.
- Garthe I, Raastad T, Refsnes PE, Koivisto A, Sundgot-Borgen J. Effect of two different weight-loss rates on body composition and strength and power-related performance in elite athletes. International Journal of Sport Nutrition and Exercise Metabolism. 2011;21(2):97–104.
- Mountjoy M, Sundgot-Borgen JK, Burke LM, et al. International Olympic Committee (IOC) consensus statement on Relative Energy Deficiency in Sport (RED-S): 2018 update. British Journal of Sports Medicine. 2018;52(11):687–697.
- Harvard Health Publishing. Calorie counting made easy. Harvard Medical School. Updated 2024.
General nutrition information, not medical advice. If you're pregnant, under 18 or managing a health condition, talk to a doctor before cutting calories.