FormaGet FormaWeight response is dynamic
Published models show that bodyweight change does not follow a simple fixed conversion indefinitely. Energy expenditure and body composition can change over time.
Free calorie deficit calculator
Calculate the target, without the false certainty.
Apply a deficit percentage to the maintenance calories you enter. See the daily and weekly energy gap, while keeping the result separate from a promise about exact weight change.
No signup. Inputs stay in this browser.
Calculate a calorie target
Enter your maintenance estimate and select a planning percentage.
This calculation runs locally and sends no data.
Daily target
Daily gap
Weekly energy gap
Formula: daily calorie target = entered maintenance calories × (1 − deficit percentage). Weekly energy gap = daily gap × 7. The tool does not convert that gap into a guaranteed amount of weight loss.
Why the calculator stops at energy arithmetic
Maintenance is an estimate
Your starting maintenance value may be wrong. Food logging, bodyweight noise, changing activity, and incomplete observations can all affect interpretation.
The percentage is your input
The tool does not label one deficit as universally safe or optimal. It only shows what your selected percentage means mathematically.
Important limits
This calculator provides general educational information, not individualized medical or nutrition care. Minors, people who are pregnant or breastfeeding, people with an eating-disorder history or concern, and people managing a medical condition should seek guidance from a qualified clinician before pursuing intentional weight loss.
Sources and better planning tools
Hall et al., 2011
A dynamic model of human energy expenditure and bodyweight change that explains why static calorie rules do not predict a linear result over time.
NIDDK Body Weight Planner
An official U.S. National Institutes of Health planning tool that models changes in diet and activity over time.
Forma adaptive TDEE methodology
How Forma frames repeated intake and smoothed bodyweight observations, with public limitations and a protected proprietary boundary.
Frequently asked questions
How is the calorie target calculated?
The calculator multiplies the entered maintenance estimate by one minus the selected deficit percentage. A 15 percent deficit from 2,500 calories gives a target of 2,125 calories per day.
Does a calorie deficit predict exact weight loss?
No. Bodyweight response is dynamic rather than perfectly linear, and maintenance expenditure, adherence, water balance, and measurement error can change the observed result.
What deficit should I choose?
This tool does not prescribe one percentage. A smaller deficit generally changes the arithmetic less and a larger deficit changes it more, but the appropriate choice depends on the person and context.
Does Forma use this exact calculation in the app?
This page publishes direct percentage arithmetic only. Forma keeps its adaptive metabolism equations, coefficients, thresholds, confidence logic, and recommendation rules proprietary.
Track what happens, then reassess.
Forma connects calories, macros, meals, steps, bodyweight trends, and workouts in one journal. A connected record can help you see whether the starting estimate matches your observations.
Download FormaPlan macros