Nutrition6 min readCalcFitLab Editorial TeamUpdated 2026-08-19

How to Set a Calorie Deficit to Lose Weight

Fat loss rests on one simple idea: spend more than you eat. Here is how to set your deficit without starving.

Calculate it for yourself

Calorie Deficit Calculator

Daily calories to reach a goal weight by a set date.

Losing weight sounds complicated but follows a simple rule. Take in less energy than your body uses over time and it draws on its reserves, so you lose fat. That gap is called a calorie deficit, and every plan to slim down starts there.

Find your TDEE first

Your Total Daily Energy Expenditure (TDEE) is how many calories you burn in a full day. It is your resting burn plus your activity. You subtract the deficit from your TDEE. Without that starting number you are only guessing.

500 kcal

Daily deficit the NHS links to steady weight loss of about 0.5 kg per week.

NHS, losing weight

How big should the deficit be

A moderate deficit of 300 to 500 kcal per day is the best trade-off for most people. You lose noticeable fat but keep enough energy for training and daily life, and you risk less muscle loss.

300 kcal deficit: slow, good for lean people who want to hold muscle.
500 kcal deficit: the classic benchmark for steady progress.
Over 750 kcal deficit: only short term and with high protein.

1,400 / 1,900 kcal

Approximate NHS lower limit of daily intake for most women and men respectively without medical supervision.

NHS, very low calorie diets

Frequently asked questions

About 0.5 to 1 percent of your body weight per week is safe and sustainable. Losing faster often costs muscle and is harder to keep off long term.

Not necessarily. Counting helps at the start to build a feel for portions. Many people later hold the result with set meals and a look at the scale.

Usually the deficit is smaller than you think or intake is underestimated. Weigh yourself over two to three weeks, take the average and adjust calories by 100 to 200.

A deficit of about 500 calories a day, or 3,500 a week, corresponds to losing roughly one pound of fat per week. You can create it by eating less, moving more, or both. Very large deficits speed things up short term but are harder to sustain and risk muscle loss.