BODY COMPOSITION CALCULATOR

How does your body
composition stack up?

Enter your stats below. Results update live.

Age35yrs
Height178cm
Weight80kg
Body fat22.0%
We preset everything here for you — feel free to play around.
Target body fat20.5%
┊ Marker = Athletic tier target (20.5%)
Weekly rate0.50% body wt/wk
0.4 kg/week — optimal pace
Strength sessions2×/week
2 sessions/week — light
Activity levelModerate
3–5×/week moderate
Your results
Progress timelineYour current stats
W0 · Now
80 kg · 22.0% fat
W5 · Goal
78.0 kg · 20.6% fat
Week 0: 80.0 kg · 22.0% body fat · 0.0 kg fat lost
Maintenance
2,701
kcal/day
BMR 1,743 · moderate
Target intake
2,261
kcal/day
440 kcal deficit
Duration to goal5 weeks
Body fat
22.0%
You have less body fat than 79% of your peers
SuboptimalAthleticAthletic
17.6 kg fat · 62.4 kg lean
17.6kg
Fat mass
Average
Fat Mass Index
5.55kg/m²
You have more fat mass index than 74% of your peers
SuboptimalAverageAthletic
Visceral fat area
65–110cm²
Average
Elevated VFA is associated with type 2 diabetes, cardiovascular disease & fatty liver risk.
Estimates. Results can vary from real data. Book DEXA for precision.
Muscle Index (ALMI)
9.46kg/m²
You have more appendicular muscle than 61% of your peers
LowAverageAthletic
62.4kg
Lean mass
Average
Lean Mass Index
18.6kg/m²
You have less lean mass index than 70% of your peers
LowAverageAthletic
Estimates. Results can vary from real data. Book DEXA for precision.
Precision metrics — DEXA only
LOCKED
These metrics can only be measured by a DEXA scan — not estimated from inputs alone.
Weight loss efficiency
DEXA only
Your Partitioning Ratio (P-ratio) — the exact proportion of lean muscle lost relative to total weight change, tracked scan-to-scan. Low ratio = you're losing fat, not muscle.
Fat by compartment
DEXA only
Trunk, arms, and legs — fat mass in kg and %, including Android/Gynoid ratio for cardiometabolic risk.
Muscle by compartment
DEXA only
Left/right arm and leg lean mass in kg. Compartmental breakdown only possible with DEXA.
Lean asymmetry
DEXA only
Left vs right arm and leg lean mass difference. Gaps >4% can signal imbalance or injury risk.
Bone density
DEXA only
Whole-body BMD g/cm² with Z-score vs age/sex peers — compartment breakdown across spine, hips, arms, legs.
Visceral fat trend
DEXA only
Metabolic age
DEXA only
Hydration index
DEXA only
Trunk lean mass
DEXA only

Population reference: NHANES White adults 20–85 (closest available UK proxy). All percentiles use the LMS Box-Cox formula: z = ((y/M)^L − 1) / (L × S/M), where L, M, S are interpolated from the NHANES LMS table. S is the absolute SD; S/M gives the coefficient of variation. BMC estimated at 4.5% of body weight. ALMI uses sex-specific appendicular fraction (M: 0.51, F: 0.47) of skeletal lean. Visceral fat is a wide-range proxy. All figures are estimates only and do not constitute medical advice, diagnosis, or treatment. Consult a qualified healthcare professional before making changes to your diet or exercise.

BODY COMPOSITION CALCULATOR

How does your body
composition stack up?

Enter your stats below. Results update live.

Age35yrs
Height178cm
Weight80kg
Body fat22.0%
We preset everything here for you — feel free to play around.
Target body fat20.5%
┊ Marker = Athletic tier target (20.5%)
Weekly rate0.50% body wt/wk
0.4 kg/week — optimal pace
Strength sessions2×/week
2 sessions/week — light
Activity levelModerate
3–5×/week moderate
Your results
Progress timelineYour current stats
W0 · Now
80 kg · 22.0% fat
W5 · Goal
78.0 kg · 20.6% fat
Week 0: 80.0 kg · 22.0% body fat · 0.0 kg fat lost
Maintenance
2,701
kcal/day
BMR 1,743 · moderate
Target intake
2,261
kcal/day
440 kcal deficit
Duration to goal5 weeks
Body fat
22.0%
You have less body fat than 79% of your peers
SuboptimalAthleticAthletic
17.6 kg fat · 62.4 kg lean
17.6kg
Fat mass
Average
Fat Mass Index
5.55kg/m²
You have more fat mass index than 74% of your peers
SuboptimalAverageAthletic
Visceral fat area
65–110cm²
Average
Elevated VFA is associated with type 2 diabetes, cardiovascular disease & fatty liver risk.
Estimates. Results can vary from real data. Book DEXA for precision.
Muscle Index (ALMI)
9.46kg/m²
You have more appendicular muscle than 61% of your peers
LowAverageAthletic
62.4kg
Lean mass
Average
Lean Mass Index
18.6kg/m²
You have less lean mass index than 70% of your peers
LowAverageAthletic
Estimates. Results can vary from real data. Book DEXA for precision.
Precision metrics — DEXA only
LOCKED
These metrics can only be measured by a DEXA scan — not estimated from inputs alone.
Weight loss efficiency
DEXA only
Your Partitioning Ratio (P-ratio) — the exact proportion of lean muscle lost relative to total weight change, tracked scan-to-scan. Low ratio = you're losing fat, not muscle.
Fat by compartment
DEXA only
Trunk, arms, and legs — fat mass in kg and %, including Android/Gynoid ratio for cardiometabolic risk.
Muscle by compartment
DEXA only
Left/right arm and leg lean mass in kg. Compartmental breakdown only possible with DEXA.
Lean asymmetry
DEXA only
Left vs right arm and leg lean mass difference. Gaps >4% can signal imbalance or injury risk.
Bone density
DEXA only
Whole-body BMD g/cm² with Z-score vs age/sex peers — compartment breakdown across spine, hips, arms, legs.
Visceral fat trend
DEXA only
Metabolic age
DEXA only
Hydration index
DEXA only
Trunk lean mass
DEXA only

Population reference: NHANES White adults 20–85 (closest available UK proxy). All percentiles use the LMS Box-Cox formula: z = ((y/M)^L − 1) / (L × S/M), where L, M, S are interpolated from the NHANES LMS table. S is the absolute SD; S/M gives the coefficient of variation. BMC estimated at 4.5% of body weight. ALMI uses sex-specific appendicular fraction (M: 0.51, F: 0.47) of skeletal lean. Visceral fat is a wide-range proxy. All figures are estimates only and do not constitute medical advice, diagnosis, or treatment. Consult a qualified healthcare professional before making changes to your diet or exercise.