How many calories should I cut to lose weight?

A deficit of about 500 calories a day produces roughly half a kilogram, or one pound, of loss per week for most people. That rate is sustainable and largely preserves muscle. Deficits much larger than that increase muscle loss, make adherence harder, and rarely speed things up as much as the arithmetic promises.

Where does the 7,700 calorie figure come from?

It is the widely used estimate of the energy stored in a kilogram of body tissue, equivalent to about 3,500 calories per pound. It is an approximation: real losses include water and some lean tissue, so actual results vary. It remains a reasonable planning number over periods of weeks.

Why does the calculator warn about very low targets?

Because sustained intakes below roughly 1,200 calories for women or 1,500 for men make it difficult to meet basic nutrient requirements and are associated with muscle loss and gallstones. Diets below those levels can be appropriate in some clinical situations, but they belong under medical supervision.

Is the 30/40/30 macro split the right one?

It is a reasonable general-purpose starting point, not a rule. Higher protein helps preserve muscle in a deficit and is more filling. Athletes in endurance sports usually want more carbohydrate; some people do better on more fat. The calorie total drives weight change far more than the split between the three.

Why am I not losing weight at the predicted rate?

Most often because intake is higher than believed — unlogged cooking oil, drinks and portions add up quickly — or because the activity level chosen was too generous. Water retention also masks fat loss for weeks at a time. Compare the trend over three weeks, not day to day.

Can I use this while pregnant or breastfeeding?

No. Energy requirements in pregnancy and lactation are substantially higher and deliberately losing weight during them is generally inadvisable. These equations are not calibrated for either situation, and the right target should come from a midwife or doctor.

Calorie Calculator: Daily Target and Macros

How to use this calculator

Choose units, then enter sex at birth, age, weight and height.
Pick the activity level that honestly describes your week.
Set the weight change per week you want — positive to lose, negative to gain, zero to maintain.

The safety check tells you whether the resulting target is sensible to attempt unsupervised.

How the calculation works

Three steps.

1. Basal metabolic rate via the Mifflin-St Jeor equation:

male:   BMR = 10 × kg + 6.25 × cm − 5 × age + 5
female: BMR = 10 × kg + 6.25 × cm − 5 × age − 161

2. Maintenance calories, by applying an activity multiplier from 1.2 (sedentary) to 1.9 (very active).

3. The adjustment. A kilogram of body tissue holds roughly 7,700 calories — about 3,500 per pound. To lose at a chosen rate:

daily adjustment = (kg per week × 7700) / 7
target = maintenance − adjustment

A worked example

A 34-year-old male, 78 kg, 175 cm, training 3 to 5 days a week, aiming to lose 0.5 kg a week.

BMR  = 10(78) + 6.25(175) − 5(34) + 5 = 1708.75
TDEE = 1708.75 × 1.55 = 2648.56
adjustment = (0.5 × 7700) / 7 = 550
target = 2648.56 − 550 = 2098.56


Maintenance	2,649 kcal
Daily target	2,099 kcal
Protein	157 g
Carbohydrate	210 g
Fat	70 g

The macros use a 30/40/30 split by calories. Protein and carbohydrate supply 4 calories per gram, fat 9 — which is why the fat figure in grams looks small next to the others despite being the same share of energy.

Choosing a rate of loss

0.5 kg (about 1 lb) a week is the standard recommendation. It is sustainable, largely preserves muscle, and requires a 550 calorie daily deficit, which most people can manage without their life revolving around it.

1 kg a week requires a 1,100 calorie deficit. For someone with a lot to lose this can be appropriate for a period. For someone already lean it usually means losing muscle and being miserable.

Faster is rarely better. Aggressive deficits increase muscle loss, worsen adherence, and frequently end in a rebound that undoes the progress. The rate that you can actually maintain for six months beats the rate that looks best on paper for three weeks.

The safety floor

The calculator flags targets below roughly 1,200 calories for women and 1,500 for men.

Below those levels it becomes genuinely difficult to meet basic vitamin, mineral and protein requirements from food, and sustained very low intakes are associated with muscle loss, gallstones and a poor relationship with eating. Very low calorie diets do have legitimate clinical uses — but under medical supervision, not from a web calculator.

If your target comes out below the floor, the fix is usually to choose a slower rate of loss or to raise the activity level through genuine additional movement.

Do the macros matter?

Less than the calorie total, but not nothing.

Protein is the one worth getting right. It preserves muscle in a deficit and is markedly more filling per calorie than fat or carbohydrate. Something in the region of 1.6 to 2.2 grams per kilogram of bodyweight is well supported for anyone training.

The carbohydrate and fat split is largely preference. Endurance athletes generally want more carbohydrate; some people find higher fat more satisfying. Both work for weight change if the calories match.

The 30/40/30 default is a reasonable general-purpose starting point, not a rule.

Common mistakes to avoid

Underestimating intake. Cooking oil, drinks, sauces, and portions eyeballed rather than weighed add up quickly — several hundred calories a day is common. This is the single most frequent reason a correctly calculated plan does not work.

Overestimating activity. Choosing “active” when you are moderate inflates maintenance by about 300 calories, which can wipe out the entire intended deficit before you begin.

Eating back exercise calories from a tracker. Tracker burn estimates are frequently overstated. Treat exercise as already included in the activity multiplier rather than as extra food earned.

Judging progress daily. Water retention masks fat loss for weeks at a time, particularly after salty meals, hard training or changes in carbohydrate intake. Compare the trend over three weeks, not day to day.

Forgetting that maintenance falls as you lose. A smaller body burns less. Recalculate every five kilograms or so, or the deficit quietly becomes maintenance.

When this calculator is not the right tool

For simply understanding what your body burns, without a weight goal attached, the BMR calculator is the cleaner answer. During pregnancy or breastfeeding these equations are not calibrated and deliberate weight loss is generally inadvisable. And for any eating disorder history, calorie targets from a calculator are not the right tool at all — that belongs with a clinician.

Calorie Calculator