Methodology
Formulas and assumptions
Core equations used across calculators.
What you should know
Every calculator here is an estimate. The goal is repeatability: a clean baseline you can test for 1–2 weeks, then adjust with real progress.
Energy equations
BMR (Mifflin–St Jeor) is used as the baseline.
| Sex | Formula |
|---|---|
| Men | 10×kg + 6.25×cm − 5×age + 5 |
| Women | 10×kg + 6.25×cm − 5×age − 161 |
TDEE is estimated as BMR × activity factor. Activity multipliers are explained in the guides.
Deficit and surplus targets
Deficit/surplus tools apply a percentage to estimated TDEE. A modest starting range is recommended because adherence beats extreme math.
Body metrics
- BMI: kg / m²
- Body fat: US Navy circumference equations (tape measure)
- Lean body mass: derived from body fat estimate
- 1RM: Epley estimate
Units
Tools support US and metric inputs. Internally we convert to metric for formulas, then render results in familiar units.
How to validate your numbers
- Run a baseline tool (TDEE or Protein).
- Follow the plan for 10–14 days.
- Review a 7‑day average weight trend and a waist metric.
- Adjust in small steps and repeat.
Start here: TDEE Calculator and Protein Intake Calculator.