Purpose and steps
Estimates resting energy with Mifflin–St Jeor, applies an activity multiplier, then uses about 3,500 kcal per pound to estimate a daily deficit.
- Choose units and use the pre-pregnancy, resting or current measurements requested by the tool; keep observation dates consistent.
- Prepare Sex used by the equation, Age, Weight, Height, Daily activity level, Weekly weight-loss target. Defaults demonstrate the model rather than your personal circumstances.
- Check the headline result and its components. A key interpretation for this tool is: Use the target as an initial estimate and adjust from observed trends.
- Compare the baseline with a changed scenario: Faster selected loss creates a larger calculated deficit, not a promise of faster real-world loss.
Input reference and units
These values reproduce the model’s demonstration. Replace them with your own records or measurements; they are not recommended targets.
On a small screen, swipe the table horizontally to see all columns.
| Parameter | Demonstration value | How to enter it |
|---|---|---|
| Sex used by the equation | Female | Use the definition shown in the field label; keep this assumption consistent when comparing scenarios. |
| Age | 30 years | Use years here. The model converts to months when the payment schedule requires it. |
| Weight | 70 kg | Use the definition shown in the field label; keep this assumption consistent when comparing scenarios. |
| Height | 170 cm | Use the definition shown in the field label; keep this assumption consistent when comparing scenarios. |
| Daily activity level | Moderately active (3–5 days/week) | Use the definition shown in the field label; keep this assumption consistent when comparing scenarios. |
| Weekly weight-loss target | 1 lb/week | Use the definition shown in the field label; keep this assumption consistent when comparing scenarios. |
Model-specific method
How this calculator produces its result
Mifflin–St Jeor BMR is multiplied by an activity factor. The selected U.S. weekly loss pace is converted using about 3,500 kcal per pound, then subtracted from estimated maintenance calories.
Energy bookkeeping and weighted allocation
Energy allocation is a weighted sum because grams of protein, carbohydrate and fat have different modeled energy densities. Subtract the energy already assigned before converting the remainder into another nutrient. Dividing remaining calories by four rather than nine would miscalculate fat grams.
A static deficit or surplus is a budgeting estimate rather than a linear prediction of body-weight change. Expenditure can adapt, measurement is imperfect and changes in water and lean tissue affect weight. Activity factors can already include exercise; adding it again may double-count energy use.
TDEE ≈ estimated resting energy × activity factor Energy from macros = 4 × protein grams + 4 × carb grams + 9 × fat grams Planned balance = intake − estimated expenditure
- kcal: energy, not food mass
- g: grams of the selected macronutrient
- Activity factor: empirical multiplier, not measured exercise energy
- Balance: model estimate over the specified period
Worked example
For a 30-year-old woman at 70 kg and 170 cm with a 1.55 activity factor, estimated maintenance is about 2,250 kcal/day. A 1 lb/week plan implies about a 500 kcal daily deficit and a target near 1,750 kcal/day.
Reproduce the default scenario
This is a separate example, calculated using the exact engine on the tool page and the defaults in the input reference above. Health examples use metric units. Displayed rounding may differ from intermediate precision.
- Estimated daily calorie target
- 1,750 kcal/day
- TDEE
- 2,250 kcal/day
- BMR
- 1,452 kcal/day
- Average daily deficit
- 500 kcal/day
Reading results without overstating them
- Use the target as an initial estimate and adjust from observed trends.
- Faster selected loss creates a larger calculated deficit, not a promise of faster real-world loss.
Assumptions and exclusions
- Energy expenditure adapts over time and food labels have measurement error.
- Very low intake, pregnancy, eating disorders, or medical conditions require professional guidance.
Sources and content notes
Toolify describes the implemented algorithm and its assumptions. Sources below support the topic or applicable rules; they do not endorse this calculator. Examples are illustrative, and published rules take precedence over simplified estimates.
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