Calorie Calculator
Turn a weight goal and a rate you choose into a daily calorie target, with the limits of that arithmetic stated.
Result
Enter age, height and current weight to see the result.
https://calcgallery.com/nutrition-energy/calorie-calculator/
How to use the Calorie Calculator
- Enter your age, height, weight and activity band to get your maintenance calories.
- Choose whether you want to lose, gain or maintain.
- Enter the weekly rate you have decided on. This page does not suggest one.
- Read the target, and read the limitations of the rule that produced it.
How it is calculated
The target is built in three steps:
1. Basal rate Mifflin-St Jeor from age, height, weight and sex2. Maintenance basal rate × the midpoint of your FAO/WHO/UNU activity band3. Target maintenance − (weekly rate × 7,700 ÷ 7)A positive rate means losing, so the daily adjustment is subtracted. For a gain it is added. If you choose to maintain, the rate is ignored entirely and the target is maintenance.
The last step converts a rate of weight change into a daily energy adjustment using 7,700 kilocalories per kilogram — the Wishnofsky figure, from a 1958 paper reasoning about the energy stored in adipose tissue. Half a kilogram a week is 3,850 kilocalories a week, or 550 a day.
The 7,700 rule, and why it overstates long-run loss
The rule assumes three things that are not true for long.
It assumes what you lose has a fixed composition. Weight lost is a mixture of fat, lean tissue and water, in proportions that vary between people and shift over the course of a diet. Those components store very different amounts of energy.
It assumes your maintenance stays put. It does not. A lighter body has less tissue to keep running and costs less to move, so maintenance falls as you lose — which means a fixed deficit shrinks in real terms every week.
It ignores metabolic adaptation. Energy expenditure drops during sustained restriction by more than the change in body size alone predicts.
The practical consequence is that the straight-line projection in the “weeks at this rate” figure is optimistic, and increasingly so the longer the horizon. A target calculated today needs recalculating as your weight changes. That is not a flaw in this page’s arithmetic; it is what the underlying rule does.
What this page will not do
It will not suggest a rate. It will not tell you what to weigh. It will not recommend a diet, a food or a pattern of eating. It converts a decision you have already made into a daily number, and states the limits of the conversion.
If the arithmetic produces a target below your estimated basal rate, the calculator reports the basal rate instead and says so. No published source supports a sustained intake below basal requirements, and the correct next step is a conversation with a clinician rather than a smaller number.
Practical tips
Recalculate every few kilograms. Maintenance moves as your weight does, and a target computed at your starting weight quietly becomes a smaller deficit than you think.
Measure against reality, not against the equation. Four to six weeks of consistent intake and regular weighing tells you more about your own maintenance than any prediction.
Weigh consistently. Same time of day, same conditions. Daily swings of a kilogram are water and gut contents and will hide a real trend completely over short periods.
A slower rate has fewer ways to go wrong. It leaves more room for the estimate to be off, needs less adaptation, and is easier to sustain long enough to matter.
The activity band matters as much as the deficit. Choosing “active” when you are sedentary can inflate maintenance by several hundred kilocalories, which will wipe out a modest deficit entirely.
With your numbers
- Maintenance at this activity level is 2,213 kcal a day
- 1 lb a week at 7,700 kcal per kilogram is 499 kcal a day
- That gives a daily target of 1,714 kcal
Quick reference
The 7,700 kcal per kilogram rule assumes fixed tissue composition and no metabolic adaptation, so it overstates long-run loss. Re-check the target as your weight changes.
| Example | Daily calorie target |
|---|---|
| Male, 30, 5 ft 10 in, 190 lb, lose 1 lb/wk | 2,328 kcal |
| Male, 30, 5 ft 10 in, 175 lb, maintain | 3,250 kcal |
| Female, 30, 5 ft 4 in, 160 lb, lose 1 lb/wk | 1,714 kcal |
| Female, 25, 5 ft 6 in, 120 lb, gain 0.5 lb/wk | 2,662 kcal |
| Male, 35, 178 cm, 85 kg, lose 0.5 kg/wk | 2,761 kcal |
| Male, 35, 178 cm, 80 kg, maintain | 3,219 kcal |
| Female, 30, 165 cm, 70 kg, lose 0.25 kg/wk | 1,922 kcal |
| Male, 22, 180 cm, 65 kg, gain 0.25 kg/wk | 3,951 kcal |
Where the numbers come from
The fixed figures this calculator relies on, and the published source each one was checked against. How the calculators are built and checked
2 sources
FAO/WHO/UNU, Human Energy Requirements (2004), chapter 5, section 5.3.1, Table 5.3, https://www.fao.org/4/y5686e/y5686e07.htm: sedentary or light 1.40-1.69, active or moderately active 1.70-1.99, vigorous 2.00-2.40.
Used for
- Lower bound of sedentary or light activity.
- Upper bound of sedentary or light activity.
- Lower bound of active or moderately active lifestyle.
- Upper bound of active or moderately active lifestyle.
- Lower bound of vigorous or vigorously active lifestyle.
- Upper bound of vigorous or vigorously active lifestyle.
Wishnofsky M, American Journal of Clinical Nutrition 6(5):542-546, 1958 (paywalled, not opened), as restated by Thomas DM et al., "Effect of dietary adherence on the body weight plateau", J Acad Nutr Diet 114(6):857-866, 2014, https://pmc.ncbi.nlm.nih.gov/articles/PMC4035446/: "the energy content of weight loss is constant at 3500 kcal/lb or 7700 kcal/kg"; and Hall KD, Int J Obes 32(3):573-576, 2008, https://pmc.ncbi.nlm.nih.gov/articles/PMC2376744/: "3500 kcal is required per pound of body weight loss, or equivalently 32.2 MJ per kg". 3,500 kcal/lb is 7,716 kcal/kg; 7,700 is the customary rounding. Both papers describe it as a rule that overstates long-run loss.
Used for
- Energy equivalent of a kilogram of body mass change. A simplification: it assumes fixed tissue composition and no metabolic adaptation.
Common questions about the Calorie Calculator
- Why did my target come out below my BMR?
- Because the arithmetic asked for a deficit larger than your maintenance minus your basal rate. When that happens the calculator reports your estimated basal rate instead of the number the subtraction produced, and says it has done so. That is a numeric guard against showing an absurd or negative figure, not advice. A target below the basal rate is a question for a clinician, not for a web page.
- Is a 500 calorie deficit safe?
- That is a clinical question and this page cannot answer it. What the arithmetic says is that 500 kilocalories a day is 3,500 a week, which the Wishnofsky figure converts to about 0.45 kilograms. Whether that rate is appropriate for you depends on your size, your health, your medication, what you are eating and a great deal else that a calculator has no access to.
- Why does my weight loss stall?
- Three things the 7,700 rule ignores. A lighter body burns less at rest and less in motion, so maintenance falls as you lose. Metabolic adaptation reduces expenditure beyond what the size change alone predicts. And what you lose is not pure fat, so the energy per kilogram changes too. The practical consequence is that a target computed today will be wrong in a few months and should be recalculated.
- Do I need to eat back exercise calories?
- It depends on whether your activity band already includes that exercise. Physical activity level is a whole-day figure, so if you chose the active band because you train regularly, the training is already counted and adding it again double-counts it. If you chose sedentary and then did something unusual, it is not counted. This page cannot tell which applies to you.
- Where does 7,700 calories per kilogram come from?
- A 1958 paper by Wishnofsky, which reasoned that a kilogram of adipose tissue stores roughly that much energy. The figure is widely used and widely criticised, because it assumes the tissue lost is a fixed composition and that nothing else about the body changes. It is a reasonable first approximation over weeks and a poor one over months.