How big a deficit is safe?

For most people, 250 to 500 calories below maintenance is a sustainable pace, giving about half a pound to a pound of loss per week. Larger deficits work faster but are harder to keep up and can cost you muscle.

Why did my target stop dropping?

We floor the daily target at a safe minimum, around 1,500 calories for men and 1,200 for women, because eating too little backfires and is hard to sustain.

Verified formulaLast reviewed July 2026

Calorie Deficit Calculator

Find the daily calories to reach your weight goal, based on your body and how fast you want to go.

Your details

Weight (lbs)

Height (ft)

Height (in)

Age

Sex

Activity level

Weekly goal

Calculated live in your browser. Nothing is stored or sent anywhere.

Awaiting details

—

Fill in your details to see your result.

A mathematical estimate based on validated equations, for education only. It is not a diagnostic tool.

The science

A calorie deficit simply means eating a little less than your body burns, and it is the honest engine behind steady weight loss. This calculator estimates your maintenance calories from your body and activity, then subtracts a sensible amount for the pace you choose, so you get a realistic daily target rather than a crash diet.

The formula

Mifflin-St Jeor BMR x activity, minus a deficit (3,500 kcal per pound)

Sources

1
Mifflin MD, St Jeor ST, et al. A new predictive equation for resting energy expenditure.
2
U.S. Dietary Guidelines for Americans (odphp.health.gov)

Common questions

This tool is for education only and is not a diagnostic device. Consult a licensed clinician before making health decisions.