Calorie deficit calculator

Find how many calories a day to eat to lose weight at a pace you choose, from a gentle 0.25 kg to 1 kg a week. Based on Mifflin-St Jeor and your activity, with a safety floor and a goal-date estimate.

The arithmetic behind a deficit

Your weight changes when the energy you eat differs from the energy you burn. This calculator estimates what you burn (your TDEE) and subtracts a daily deficit sized to your chosen pace, using the common approximation that a kilogram of body weight holds about 7,700 calories.

daily deficit = pace(kg/week) × 7,700 ÷ 7
target intake = TDEE − daily deficit
floor = 1,200 kcal (women) · 1,500 kcal (men)

That rule is a good guide for the first weeks and too optimistic over months. Research modelling long-term weight change (Hall and colleagues, The Lancet, 2011) shows that as you lose weight your expenditure falls too, so the same intake produces slower loss. Recalculate every 4–5 kg.

Choosing a pace

0.25 kg a week: the easiest to sustain; good for the last few kilos or for lifters protecting muscle.
0.5 kg a week: the default for most people.
0.75–1 kg a week: only with a large starting weight; harder to sustain and to meet protein needs.

Whatever the pace, protein helps protect muscle while you lose fat: see the protein calculator.

Questions

How many calories should I eat to lose weight?

Start from your maintenance calories (TDEE) and subtract a deficit that matches the pace you want. Losing about 0.5 kg (1 lb) a week takes a deficit of roughly 550 calories a day. This calculator does the arithmetic and warns you if the target falls below a common safety floor.

What is a safe calorie deficit?

For most adults, a pace of 0.25–1 kg (0.5–2 lb) a week. Many clinicians avoid going below about 1,200 calories a day for women and 1,500 for men without supervision, because it becomes hard to get enough protein and micronutrients.

Why did my weight loss slow down?

As you lose weight, you burn fewer calories, and the body adapts somewhat. The classic 7,700 calories per kilogram rule overestimates long-term loss. Recalculate your target every 4–5 kg, or use a tracker with an adaptive target.

Do I need to count calories to be in a deficit?

Not strictly, but people who track their intake consistently tend to lose more weight than people who do not. A tracker that makes logging fast is the easiest way to know whether you are actually in a deficit.

Sources

Hall KD, Sacks G, Chandramohan D, et al. Quantification of the effect of energy imbalance on bodyweight. Lancet. 2011;378(9793):826–837.
Burke LE, Wang J, Sevick MA. Self-monitoring in weight loss: a systematic review of the literature. J Am Diet Assoc. 2011;111(1):92–102.
U.S. Centers for Disease Control and Prevention. Steps for losing weight (gradual, steady loss of 1–2 lb per week).

Built and checked by Ingrid Solberg. Last reviewed October 22, 2026. All formulas: formulas & sources.