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Calorie Deficit Calculator

Find out how many calories to eat daily to reach your target weight at a safe, sustainable pace. Based on your TDEE and your chosen weekly rate of weight loss.
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How it works

Plan your deficit in three steps

1. Enter your current stats

Provide your age, sex, height, current weight, and activity level. The calculator uses these inputs to estimate your TDEE — the total calories you burn each day.

2. Set your target weight and pace

Input your goal weight and select your preferred weekly rate of loss: 0.25 kg, 0.5 kg, or a custom amount. The calculator checks whether the target pace is considered safe before proceeding.

3. Get your daily calorie target

The result shows your recommended daily intake to achieve the chosen deficit, along with an estimated number of weeks to reach your goal weight at that rate.

FAQ

Common questions

A calorie deficit occurs when you consume fewer calories than your body expends in a given day. Since stored body fat is used as an energy reserve, a sustained deficit results in fat loss over time. Approximately 7,700 calories equal one kilogram of body fat, meaning a daily deficit of 500 calories would theoretically result in roughly 0.5 kg of fat loss per week. In practice, the rate of loss varies due to metabolic adaptation, water retention fluctuations, and changes in muscle mass composition.
A large deficit tends to produce faster short-term weight loss but carries significant drawbacks. Eating too few calories — typically defined as below your BMR — increases the risk of muscle loss, nutritional deficiencies, fatigue, hormonal disruption, and a progressively slower metabolism. Most dietitians recommend a moderate deficit of 250–500 calories below TDEE. This produces steady, sustainable progress while preserving muscle mass and energy levels. Very aggressive deficits are difficult to maintain and frequently lead to rebound weight gain after the restriction ends.
Weight loss is not a perfectly linear process, and the figures produced by this calculator are estimates. Actual results depend on metabolic rate (which adapts to reduced intake over time), day-to-day hydration changes, hormonal fluctuations, and whether weight lost is fat, muscle, or water. A common pattern is rapid initial loss from water and glycogen depletion, followed by slower fat loss as the body adjusts. Tracking your intake and body weight weekly over three to four weeks gives a more accurate picture of your personal calorie needs than any formula can.
Most health guidance advises against eating below 1,200 calories per day for women or 1,500 calories for men without medical supervision. Going below your BMR for extended periods is generally considered risky and can lead to the adverse effects described above. This calculator flags when a chosen deficit would result in an intake below recommended minimum thresholds. If you need to lose weight rapidly for a specific medical reason, work with a registered dietitian or doctor who can supervise a very-low-calorie plan safely and monitor for complications.

Keep going

Related tools

TDEE Calculator

Calculate your total daily energy expenditure as the baseline for your deficit.

Open tool →

BMR Calculator

Find your resting calorie burn to ensure your deficit stays above safe minimums.

Open tool →

Macro Calculator

Plan your protein, carbs, and fat within your deficit calorie budget.

Open tool →

BMI Calculator

Track your weight classification progress alongside calorie management.

Open tool →

About the Calorie Deficit Calculator

The Calorie Deficit Calculator helps individuals determine a safe daily calorie intake for weight loss based on their current stats and target weight. It is used by people at various stages of a weight management journey — from those starting out to those refining an existing plan. By linking the deficit to a personalised TDEE calculation, the tool grounds recommendations in the individual’s actual energy expenditure rather than a generic average figure.

Benefits

  • Calculates a personalised daily calorie target based on TDEE, not a one-size-fits-all number
  • Flags when a target intake falls below recommended safe minimum thresholds
  • Shows an estimated timeline to goal at the selected weekly rate of loss
  • Supports both metric and imperial unit inputs for international use

Privacy

All personal data entered into this calculator is processed locally in your browser and is never transmitted to or stored on any server.