Body Biometrics

Glossary & field-test guide

1RM (one-rep max)
The heaviest weight you could lift exactly once with good form. You don't have to test it. Use the "by reps" input mode and the calc estimates it: Epley formula = weight × (1 + reps/30). Example: 32 kg KB swing × 20 reps ≈ a 1RM of ~53 kg-equivalent.
×BW (times bodyweight)
How heavy a lift is relative to your own weight. Bodyweight squat with 60 kg on the bar at 100 kg BW = 0.6× BW. Bodyweight-only dip = 1.0× BW (you ARE the load).
Bodyweight dips / pull-ups
Enter 0 in the "added weight" field if you don't strap on extra plates. The "+kg" means belt-loaded EXTRA weight, on top of your body.
Sit-Rise Test (SRT)
Sit cross-legged on the floor → stand back up. Start at 5 points each direction (10 total). Subtract 1 for each support used (hand, knee, forearm, leaning on leg). Subtract 0.5 for any wobble. Score <8 = retest after a month of training.
Rockport 1-mile walk
Walk 1 mile (1.609 km) on flat ground as fast as you can without jogging. Record total minutes & your heart rate the second you stop. Plug both in. Calculator estimates VO₂ max from Kline (1987).
Cooper 12-min run
Run as far as you can in 12 minutes. Enter total meters covered. Easier on a track. Skip if you can't run yet -- Rockport is fine.
VO₂ max
Max oxygen your body can use during exercise (ml/kg/min). The single best longevity predictor in fitness science.
BMR vs TDEE
BMR = calories burned at total rest (alive but in a coma). TDEE = BMR × activity. Eat at TDEE to maintain, below to lose, above to gain.
FFMI
Fat-Free Mass Index. Like BMI but only counts your lean mass. 18-20 = average male, 22-25 = strong, 25+ = elite. Caps natural at ~25.
WHtR (waist÷height)
The single best simple risk metric: keep waist under half your height. Newer research has it overtaking BMI clinically.
BRI (body roundness)
Treats your body as an ellipse based on height + waist. Below 3.4 = lean. Above 6.9 = elevated visceral fat risk.
MAP (mean arterial pressure)
Average pressure during one cardiac cycle. Calculated as dia + (sys−dia)/3. Healthy 70-100 mmHg.
Karvonen HR zones
Heart-rate training zones based on your reserve (max − resting). Z2 = the famous "easy aerobic" pace. Lots of Z2 builds your engine.
Biology
Body
Frame & BP
Lifestyle
Strength (switch input mode)
Skip with 0 if you don't know.
"+kg added" = belt/vest weight ON TOP of bodyweight. Bodyweight-only = 0.
Enter your best set: weight × reps. Calc estimates 1RM via Epley.
Field Tests
Optional. Skip with 0. See Glossary above.
Body composition
Body Fat % Navy + RFM avg
What this is: Estimated % of your weight that is fat tissue.
How to read: Healthy male 10-20%, female 18-28%. Anything 5+ over upper bound = visible health risk.
Three methods averaged:
  • Navy: tape measure (waist + neck + hips). Accurate within ±3.5%.
  • RFM: Relative Fat Mass -- height ÷ waist only. Newer, validated against DEXA.
  • BMI-est: Deurenberg formula from BMI + age. Worst for muscular people.
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Body Fat
Lean Mass--
Fat Mass--
FFMI ?--
FFMI: Fat-Free Mass Index. Like BMI for lean mass only. 18-20 average male, 22-25 strong, 25+ elite/uncommon naturally.
Navy-- RFM-- BMI-est--
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Body Roundness BRI · Thomas 2013
BRI models your torso as an ellipse. Uses only height + waist. Captures visceral (belly) fat risk that BMI misses entirely.
Read: <3.4 lean · 3.4-6.9 average/elevated · >6.9 high cardiometabolic risk.
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BRI Score
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Lower = leaner middle. Improves fast as you lose belly fat.
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Central Obesity WHR · WHtR
Belly-fat distribution metrics -- visceral fat is the dangerous kind.
  • Waist÷Height (WHtR): the simplest, strongest. Target <0.50.
  • Waist÷Hip (WHR): WHO classic. M<0.95, F<0.85.
  • Conicity: geometric "cone-ness" of torso. <1.25 healthy.
  • ABSI: standardized waist for height+BMI. <0.08 ideal.
Waist ÷ Hip (WHR)--
Waist ÷ Height--
Conicity Index--
ABSI--
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WHtR target < 0.50
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BMI Status WHO Classes
BMI = weight ÷ height². Crude population metric, doesn't see muscle. Use alongside Body Fat %, not instead.
Even within "healthy" 18.5-24.9, the upper end (23-25) carries more risk than the middle. The bar reflects this.
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Body Mass Index
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<18.5 under · 18.5-22.9 optimal · 23-24.9 high-healthy · 25-27.4 over · 27.5-29.9 borderline · 30-34.9 obese I · 35-39.9 obese II · ≥40 obese III
Energy & nutrition
Daily Calories Mifflin-St Jeor
TDEE = Total Daily Energy Expenditure. What you burn living + moving.
Eat at TDEE to stay the same weight. Below to lose. Above to gain.
500 kcal/day deficit ≈ 0.45 kg fat loss/week. Max sustainable: 0.5-1% of bodyweight per week.
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TDEE (maintain)
Cut goal (-500)--
Maintain--
Lean bulk (+300)--
BMR Comparison 4 formulas
BMR = Basal Metabolic Rate. Calories you'd burn lying perfectly still all day.
Different formulas use different inputs:
  • Mifflin-St Jeor: most accurate for non-athletes, including obese.
  • Harris-Benedict: classic 1918, slightly overestimates.
  • Katch-McArdle: uses lean body mass -- better if you have muscle.
  • Cunningham: similar to Katch, used in athletics.
Range shown = the spread between formulas. Use as a confidence band.
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kcal/day at rest
Mifflin-St Jeor-- Harris-Benedict-- Katch-McArdle-- Cunningham--
Mifflin most accurate for the obese (validated)
Macros Cut
Protein 4 kcal/g · Carbs 4 kcal/g · Fat 9 kcal/g.
On a cut, protein matters most: 1.6-2.2 g per kg spares muscle while you lose fat.
For obese (BMI ≥30), this calc uses your adjusted body weight as the basis to avoid prescribing too much protein.
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target calories
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Protein g
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Carbs g
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Fat g
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Hydration Adjusted
Base = 35 ml/kg bodyweight. Adds ~0.5 L per activity tier and up to 0.7 L for hot/humid climate. Sweat heavily? Add ~500 ml per training hour on top.
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Liters / day
Base (35 ml/kg)--
+ Activity--
+ Climate--
Cups (250 ml) --
Targets & projection
Ideal Weight 4 formulas + ABW
Four classic clinical formulas (Devine, Robinson, Miller, Hamwi). Treat the range as your goal, not any single number.
Adjusted BW (ABW): when you're well above ideal, this is what clinicians use for protein/drug dosing. Formula: IBW + 0.4 × (current − IBW).
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kg target range
Devine-- Robinson-- Miller-- Hamwi--
BMI 22 target--
Adjusted BW--
Weight Trajectory From cut goal
Based on 7700 kcal per kg of fat. Uses your current cut deficit to predict weekly loss and time to ideal weight.
Reality check: real-world plateaus, water shifts, and metabolic adaptation make actual progress slower than math suggests. Aim for 0.5-1% BW/wk loss for sustainability.
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kg / week (est)
To target--
Time est.--
Goal date--
% BW/wk--
Lean Mass Potential Casey Butt
Estimates the maximum lean (muscle) mass a drug-free trainee with your skeletal frame (wrist + ankle) can attain at ~10% body fat. Based on data from elite natural bodybuilders. Most lifters never reach 90% of this without years of dedicated training.
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Max Lean Mass (drug-free)
Frame--
Current LBM--
Remaining--
Metabolic Age BMR / kg LBM
Metabolic age compares your BMR per kilogram of lean body mass to population averages by age. This normalizes out body size so a tall/heavy person isn't automatically "young."

Honest caveat: this metric was popularized by bioimpedance scale brands and is not clinical. Mostly tracks lean-mass density. For something more predictive of longevity, see Fitness Age (next card).
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years
Chronological--
Difference--
BMR / kg LBM--
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Fitness Age NTNU · HUNT3
Fitness Age from the NTNU/HUNT3 study (Nes et al., 2013). Uses VO₂ max + resting HR + waist + sex to estimate the age at which the average person has your cardiorespiratory profile.

Lower fitness age = lower all-cause mortality risk. This is the metric Tim Ferriss popularized and the Norwegian researchers validated against actual longevity data. Far more meaningful than scale-based "metabolic age."

Improves dramatically as you do Z2 cardio + lose visceral fat.
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years
Chronological--
Difference--
VO₂ max used--
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Cardiovascular fitness
VO₂ Max Multi-method
VO₂ max: max oxygen your body uses during peak exercise (ml/kg/min). One of the strongest single predictors of all-cause mortality.
  • Resting HR-based (Uth): rough estimate, requires only resting heart rate. The lower your RHR, the higher this estimates. Fitness people: this is gym-bro level accurate.
  • Rockport: walk 1 mile fast, take HR at finish. Validated, accurate within ±3-5 ml/kg/min.
  • Cooper: 12-minute run, max distance. Most accurate of the three for fit people.
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ml / kg / min
METs (≈ exercise intensity)--
Max HR (220-age)--
VO₂ from Rockport--
VO₂ from Cooper--
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HR Zones Karvonen
Heart rate zones based on your HR reserve = max HR − resting HR. Reserve method is more accurate than %max alone.
Z2 ("conversational pace") is the magic zone -- most aerobic adaptations happen here. 2-4× per week, 30-60 min each, builds your engine for life.
Z1Recovery 50-60%--
Z2Aerobic 60-70%--
Z3Tempo 70-80%--
Z4Threshold 80-90%--
Z5VO₂ max 90-100%--
Z2 = should be able to talk in full sentences. Z5 = couldn't finish this one.
Blood Pressure AHA 2017
AHA 2017 categories. Note: 120/80 is now "Elevated" not optimal -- guidelines tightened in 2017.
Optimal: <120 AND <80
Elevated: 120-129 AND <80
HTN-1: 130-139 OR 80-89
HTN-2: ≥140 OR ≥90
Crisis: ≥180 OR ≥120
Single readings can be misleading -- track 5-minute averages over a week.
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mmHg sys/dia
MAP--
Pulse pressure--
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Sit-Rise Test Mortality predictor
Protocol: Sit cross-legged on the floor → stand back up. Start with 10 points (5 down + 5 up). Subtract 1 for each support used (hand, knee, forearm, leg). Subtract 0.5 for any wobble.
Why it matters: Validated in 4000+ adults aged 46-75. Score <8 was associated with 2-5× higher 6-year mortality (Araújo, Eur J Prev Cardiol 2025). Tests strength + flexibility + balance + body composition all at once.
Improving: single-leg work, hip mobility, core, losing belly fat.
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/ 10 score
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Sit cross-legged → stand. No hands, knees, forearms. -1 per support, -0.5 per wobble.
Strength & sleep
Strength Standards ×BW Ratio
1RM mode: enter your one-rep max in kg. Shows ratio of lift to bodyweight, vs intermediate trainee standards.
Reps mode: enter your best set (weight × reps). 1RM is estimated via Epley: 1RM = w × (1 + r/30). Accurate up to ~10 reps.

Bar fills toward each lift's "intermediate" trainee standard (Squat 1.5×BW, Bench 1.25×, DL 2.0×, OHP 0.85×, Pullup 1.5×, Dip 1.6×). Past that = advanced/elite territory.

For pull-ups and dips: your bodyweight IS the load. Bar shows the ratio (BW + added) ÷ BW. So bodyweight-only dip at 115 kg BW = 1.0× (i.e. you press your own 115 kg). If you strap on 30 kg = 1.26×.
Squat--
Bench--
Deadlift--
OH Press--
Pull-up--
Dip--
1RM in kg or estimated from reps × weight (Epley). Pull-up/Dip count bodyweight as the load.
Sleep Target 5 cycles
Sleep happens in ~90 min cycles. 5 full cycles = 7.5 h. Adding 15 min sleep latency → 7h 45m total in bed. Bedtime here = wake time minus 7h 45m. Waking between cycles avoids that groggy "sleep inertia" feeling.
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Bedtime Target
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Wake
7h 45m
Total
5
Cycles