What this calculator gives you
This tool starts from the same place as the TDEE calculator: your maintenance calories, worked out from the Mifflin-St Jeor equation and your activity level. Then it adds or subtracts a fixed daily amount to give you five practical targets.
It is designed for adults planning a diet phase. If you just want to know what you burn, the TDEE page is enough. If you want to know what to eat to change your weight, you are in the right place.
How to use it
Enter sex, age, height, weight and a realistic activity level. The results table shows maintenance plus four goals. Choose the one that fits your timeline and how much hunger you can tolerate, then stick with it for at least two to three weeks before judging.
| Target | Daily change | Expected pace |
|---|---|---|
| Maintain | 0 kcal | Weight stable |
| Mild weight loss | -275 kcal | About 0.25 kg (0.5 lb) a week |
| Weight loss | -550 kcal | About 0.5 kg (1 lb) a week |
| Extreme weight loss | -1,100 kcal | About 1 kg (2 lb) a week |
| Mild weight gain | +275 kcal | About 0.25 kg (0.5 lb) a week |
| Weight gain | +550 kcal | About 0.5 kg (1 lb) a week |
Where the numbers come from
The targets rely on a long-standing approximation: a kilogram of body weight change is worth about 7,700 kcal, and a pound about 3,500.
Daily change = weekly target (kg) x 7,700 / 7
0.5 kg x 7,700 / 7 = 550 kcal per day
So a 550 kcal daily deficit should, on paper, take off half a kilogram a week.
Why the 7,700 rule is only a starting point
Real weight loss slows over time. As you get lighter, your maintenance drops, and your body adapts by moving a little less and running a little more efficiently. Research by Kevin Hall and colleagues showed that the simple rule overstates long-term loss because it ignores this.
Early on the opposite happens. The first week of a diet often shows a big drop that is mostly water and stored carbohydrate, not fat. Do not let it set your expectations for week five.
The practical answer is to treat your target as a hypothesis. Weigh yourself daily, compare weekly averages, and adjust by 100 to 200 kcal if progress is clearly faster or slower than planned.
Safety floors
The calculator flags any target that falls below 1,200 kcal a day for women or 1,500 kcal a day for men. Below these levels it becomes hard to get enough protein, vitamins and minerals from food, and losing muscle becomes much more likely.
The extreme option is labelled that way for a reason. A 1 kg weekly loss is reasonable for some people with a lot of weight to lose, but for someone already fairly lean it usually means lost strength, poor sleep and a diet that ends early. Most lifters do best losing 0.5 to 1% of body weight a week.
Pregnant or breastfeeding, under 18, or with a history of disordered eating? Please get personalised advice from a doctor or registered dietitian instead of following a calculator target.
Worked example
A 35-year-old woman, 163 cm (5 ft 4 in), 74 kg (163 lb), lightly active. Her BMR is 10 x 74 + 6.25 x 163 - 5 x 35 - 161 = 1,423 kcal, and her maintenance is 1,423 x 1.375 = 1,956 kcal.
| Target | Calories a day |
|---|---|
| Maintain | 1,956 |
| Mild weight loss | 1,681 |
| Weight loss | 1,406 |
| Extreme weight loss | 856 (flagged: below 1,200) |
| Mild weight gain | 2,231 |
| Weight gain | 2,506 |
The extreme target is flagged because it falls well below the 1,200 kcal floor. For her, the weight loss option at around 1,400 kcal is the realistic choice, and it should take off roughly 2 kg (4.4 lb) a month at first.
This shows why smaller and less active people have less room for aggressive deficits. A fixed 1,100 kcal cut is a big share of a small maintenance. Increasing daily steps is often a better way to widen the gap than eating less still.
Making the target work in the gym
Calories decide whether you lose or gain. Protein and training decide what you lose or gain. In a deficit, keep lifting heavy and keep protein high so the weight that comes off is fat rather than muscle. The protein calculator gives you a daily figure, and the macro calculator builds the full split.
When gaining, a small surplus is enough. Beginners can add muscle quickly; experienced lifters gain mostly fat beyond about 0.25 kg a week. Our guide to bulking vs cutting helps you choose, and the push pull legs plan gives a surplus something to build.
Frequently asked questions
How many calories should I eat to lose weight?
Start about 500 kcal below your maintenance, which the calculator shows as the weight loss target. Adjust after two to three weeks based on how your average weight is moving.
Is 1,200 calories a day safe?
For many women it is a sensible lower limit, not a goal. For most men and active women it is too low to meet nutrient needs or keep muscle. Going lower should be medically supervised.
Why did I lose so much weight in the first week?
Early losses are mostly water and stored carbohydrate. Fat loss follows the slower, steadier pace the calculator predicts.
Does 3,500 calories always equal one pound?
It is a useful approximation, not a law. Your maintenance falls as you lose weight, so long-term loss is usually slower than the simple rule predicts.
Should I eat back calories burned in workouts?
No. Your activity level already includes training. Adding workout calories again is one of the most common reasons a deficit disappears.
References
- Hall KD, Sacks G, Chandramohan D et al. Quantification of the effect of energy imbalance on bodyweight. Lancet. 2011;378(9793):826-837
- Mifflin MD, St Jeor ST, Hill LA et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241-247
- Helms ER, Aragon AA, Fitschen PJ. Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. J Int Soc Sports Nutr. 2014;11:20
Results are estimates for healthy adults and are not medical advice. See our medical disclaimer.
