ForgeByte/Fat2Fit
Fat2Fit · Free tool

Calorie deficit calculator

Estimate your maintenance calories, then see the daily target for the pace of weight loss you choose.

–Maintenance
–Daily deficit
–Daily target

General estimate for adults, not medical advice. Talk to a doctor or dietitian if you are pregnant, have a medical condition, or have a history of disordered eating.

Hit your numbers without the math

Fat2Fit is an AI fitness coach that runs on your iPhone. Point at a plate — it names every food and totals your calories & macros in seconds. No cloud. No ads. Fat2Fit is free: every feature, for everyone.

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Questions

What is a calorie deficit?

A calorie deficit means eating fewer calories than you burn. Over time your body makes up the difference from stored energy, which leads to weight loss.

How is the daily target calculated?

Maintenance calories are estimated with the Mifflin-St Jeor equation and your activity level. The calculator then subtracts about 500 calories a day for each pound per week you want to lose, a common rule of thumb.

How fast should I lose weight?

Many guidelines suggest about 1 to 2 pounds per week at most. Slower is usually easier to maintain. The calculator warns you when a target drops very low.

Is my data saved or sent anywhere?

No. The calculation runs in your browser and nothing you type is sent to a server.