Calorie Deficit Scenario Calculator

This page models a user-selected subtraction from an equation-based daily energy estimate. It shows arithmetic scenarios, not a prescribed intake or a forecast of actual weight change.

Inputs and assumptions

Choose sex, metric or imperial units, age, height, weight, a product-defined activity factor, and a subtraction of 250, 500, 750, or 1,000 calories per day. The starting scenario is male, age 30, 75 kg, 178 cm, factor 1.55, with a 500-calorie subtraction. Ages are limited to 18–100; active height and weight values must be positive.

The activity factors 1.2, 1.375, 1.55, 1.725, and 1.9 are visible product-defined scenario assumptions. They are not health recommendations. All four subtraction choices are user scenarios; none determines that the subtraction is appropriate.

Method and example

First, the Mifflin equation estimates resting energy:

$BMR=10w+6.25h-5a+s$

where $w$ is kilograms, $h$ is centimeters, $a$ is age, and $s$ is 5 for the male equation or −161 for the female equation. Next:

$TDEE=BMR\times\text{activity factor}$ $\text{scenario calories}=TDEE-\text{selected subtraction}$

For the starting values, BMR is:

$10(75)+6.25(178)-5(30)+5=1717.5$

Applying 1.55 gives $2662.125$ calories, and subtracting 500 gives $2162.125$. The shown results are 1,718 calories for BMR and 2,162 calories for the daily scenario.

The static energy-equivalent line divides seven days of the selected subtraction by 7,700 calories/kg in metric mode or 3,500 calories/lb in imperial mode, then multiplies by 4.33. The 7,700, 3,500, and 4.33 values are explicit product-defined scenario assumptions, not health recommendations and not predictions of body weight.

Scenario comparison workflow

1. Start with the resting energy calculator if REE is the only number you need.
2. Select an activity-factor assumption and retain that factor with the result.
3. Compare one subtraction at a time and record both TDEE and the selected amount.
4. Reject any scenario that you are treating as a prescription without individualized professional review.
5. Revisit the assumptions rather than treating a rounded result as a fixed allowance.

This page cannot determine whether a deficit is appropriate. It is not for children, pregnancy, eating-disorder recovery, underweight users, or anyone needing a prescribed diet. Dynamic changes in energy use and body weight are not represented.

Sources

• Mifflin et al., A new predictive equation for resting energy expenditure — resting-energy equation.
• NIDDK, Body Weight Planner — dynamic body-weight planning and limitations of static arithmetic.
• CDC, Losing Weight — general public-health context.