Body composition

Female Athlete Formula Suite

Female forms of the common formulas: FFMI, Mifflin-St Jeor BMR, Gulati max heart rate and BMI-based body fat, with the caveats for your life stage.

Result

FFMI (fat-free mass index)

16.2kg/m²

BMR (Mifflin-St Jeor)

1,379kcal/day

Max heart rate (Gulati)

178bpm

Body fat used

29.6%

Typical VO2max, untrained, your age

32ml/kg/min

22 kg/m² is a rough reference for natural women, not a measured ceiling.

Your FFMI

16.2 kg/m²

Target: Reference 22

Rough reference

22.0 kg/m²

The FFMI reference of 22 is a rough guide: Kouri's 1995 natural ceiling of about 25 was measured in men, and no comparable study exists for women.
Body fat is estimated from BMI and age (Deurenberg 1991), so FFMI inherits that estimate's error, often several points for lean or muscular women. A measured value is better.
VO2max here is the average for untrained women of your age, not a measure of your fitness; a field test gives your own.
Resting metabolism runs slightly higher in the luteal phase than the follicular phase, so treat BMR as a cycle midpoint.

Education, not medical advice. The result comes only from the published formula and your inputs. How we check our formulas.

Formula Female Athlete Formula Suite
Female athlete energy availability (RED-S): EA = (intake_kcal − exercise_kcal) / FFM_kg, where EA below 30 kcal/kg is clinically low per IOC 2018 consensus.

Body composition Body Fat Percentage Calculator
Estimate body fat percentage using the U.S. Navy circumference method.
Nutrition TDEE Calculator
Estimate your daily energy expenditure with Mifflin-St Jeor + activity factors.
Nutrition Macro Calculator
Convert calorie targets into protein, carbs, and fat grams for your goal.
Planning Calorie Deficit Calculator
Estimate required daily calorie deficit for a target timeline and bodyweight change.

13 min read Female Athlete Physiology: Where Formulas Fail
Female-athlete physiology: where standard fitness formulas (TDEE, body-comp, 1RM) under- or over-predict, and the corrections backed by current literature.
7 min read Female Athlete Formula Suite: A 30-Year-Old in Regular Cycle
Female athlete formulas for 65 kg, 168 cm, 24% body fat, regular cycle. The luteal-versus-follicular caloric drift and where male equations fail.
11 min read Hybrid Athlete Macro Splits
Hybrid athlete macros: the split between strength and endurance days, periodised carbs around hard sessions, and protein scaling for two-stress training.

The same calculation as a JavaScript module you can import. It runs where you import it, with no request, key or rate limit.

import { compute } from "https://aifithub.io/engines/female-athlete-formula-suite.js";