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Calorie Deficit Calculator

Find your daily calories to lose, maintain or gain weight.

Details

Results

Maintenance calories -
Mild loss (−0.5 lb/wk) -
Weight loss (−1 lb/wk) -
Weight gain (+1 lb/wk) -
BMR -

Estimates only - not medical advice.

How it works

The calculator estimates your BMR using the Mifflin-St Jeor equation, then multiplies by your activity level to get your maintenance calories (TDEE). From there it subtracts your chosen deficit. A 500-calorie daily deficit maps to roughly one pound of loss per week, based on the long-standing estimate that a pound of fat stores about 3,500 calories. Results slow in practice as body mass drops, so recalculate every few weeks.

The 3,500-calorie rule of thumb: a sustained daily deficit of 500 calories creates a weekly shortfall of 3,500 calories, which tracks to roughly one pound of fat loss per week. Results vary with metabolism, adherence and how much weight has already been lost.

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Good to know

FAQs

How many calories to lose weight?

Start by finding your TDEE, then subtract your target deficit. A 500-calorie daily deficit is the common starting point, producing roughly one pound of loss per week. Smaller deficits (250 to 300 calories) are gentler and often easier to sustain long term.

What is TDEE?

Total Daily Energy Expenditure: all the calories your body burns in a typical day, including resting metabolism, movement, exercise and the energy used to digest food. It is the number your calorie target is measured against.

What is BMR?

Basal Metabolic Rate: the calories your body uses at complete rest, just to maintain basic functions. This calculator uses the Mifflin-St Jeor equation, which is the most widely validated for general use.

Is a bigger deficit better?

Not usually - very low intake risks muscle loss and is hard to sustain. 0.5-1 lb/week is healthy.

Is this medical advice?

No - consult a doctor or dietitian before major diet changes.