Calorie Deficit Calculator

Daily calories and time to reach your goal weight

Not sure? Work it out with the BMR and TDEE calculator.

Weekly loss

Daily calories

1,950kcal / day

A deficit of about 550 kcal a day (0.6% of body weight per week).

Estimated goal date

27 Dec 2026

About 10 weeks at 0.5 kg a week. Real progress is not a straight line.

More free tools: BMR and TDEE · Macros · Protein · Water · Calorie deficit

How the calorie deficit calculator works

From weekly loss to daily calories

About 7,700 kcal ≈ 1 kg of body fat
Daily deficit = weekly loss (kg) × 7,700 ÷ 7
Daily target = TDEE − daily deficit

The calculator never suggests fewer than 1,200 kcal a day and warns you when your chosen pace would need more than that.

Worked example

TDEE of 2,500 kcal, losing 0.5 kg a week: 0.5 × 7,700 ÷ 7 = 550 kcal deficit, so about 1,950 kcal a day. Going from 85 kg to 80 kg takes about 10 weeks.

Choosing a pace

  • 0.25 to 0.5 kg a week: easiest to sustain and best for keeping muscle, especially if you are already fairly lean.
  • 0.5 to 1% of body weight a week: a common target for most people.
  • Faster than 1% a week: harder to stick to, more hunger and more muscle loss.

Real progress is not a straight line. Water and food weight move the scale day to day, and your TDEE drops a little as you lose weight. Re-check your numbers every few weeks, or let an adaptive TDEE do it for you.

This is general guidance for healthy adults, not medical advice. Do not diet without medical guidance if you are pregnant, under 18 or have a history of eating disorders.

Frequently asked questions

How big should my calorie deficit be?

For most people a deficit that produces 0.5 to 1% of body weight loss per week works well, often around 300 to 600 kcal a day.

How long will it take to reach my goal weight?

Divide the weight you want to lose by your weekly rate. Losing 5 kg at 0.5 kg a week takes about 10 weeks.

Is 1 kg a week too fast?

For many people, yes. It needs a deficit of about 1,100 kcal a day, which is hard to sustain and increases muscle loss unless you have a lot of weight to lose.

Why does weight loss slow down?

As you lose weight your body uses less energy, so the same intake creates a smaller deficit. Recalculate your TDEE every few weeks.