Developer Utilities
Small developer utilities that save a trip to a random website. Encode and decode Base64, explain a regex, build UTM links, generate QR codes and vCards, and more — the everyday helpers. Free in your browser, and available by API when you need them in a script.
Developer Utilities
Body surface area calculator
Boyd formula BSA, free
POST /health/bsa-boyd$0.002Developer Utilities
Body surface area Fujimoto calculator
BSA from height and weight
POST /health/bsa-fujimoto$0.002Developer Utilities
Lean bulk calorie calculator
surplus % from maintenance, free
POST /health/bulking-calories$0.002Developer Utilities
Calorie target for weight goal
daily intake by date range, free
POST /health/calorie-goal-by-date$0.002Developer Utilities
Calorie cycling zigzag planner
weekly intake high/low days
POST /health/calorie-zigzag$0.002Developer Utilities
Carb intake calculator
daily grams from calories and percent, free
POST /health/carb-intake$0.002Developer Utilities
Conicity index calculator
central fat from waist, weight & height
POST /health/conicity-index$0.002Developer Utilities
CSS swim training pace calculator
critical swim speed interval offsets
POST /health/css-training-paces$0.002Developer Utilities
Cutting phase calorie calculator
intake from TDEE and deficit %
POST /health/cutting-calories$0.002Developer Utilities
Dietary energy density calculator
kcal per gram of a meal
POST /health/energy-density-diet$0.002Developer Utilities
Calories from macronutrients calculator (Atwater)
POST /health/energy-from-macros$0.002Developer Utilities
EPOC afterburn estimate calculator
intensity and duration
POST /health/epoc-estimate$0.002Developer Utilities
Fat-free mass calculator
FFM in kg from weight and body fat, free
POST /health/fat-free-mass-calc$0.002Developer Utilities
Normalized FFMI calculator
height-adjusted fat-free mass index, free
POST /health/ffmi-normalized$0.002Developer Utilities
Fiber intake per 1000 kcal calculator
14 g per 1000 calories
POST /health/fiber-per-1000kcal$0.002Developer Utilities
FTP from 20-minute test calculator
estimate threshold power free
POST /health/ftp-from-20min$0.002Developer Utilities
Goal calorie adjustment
fat loss, maintain or muscle gain %
POST /health/goal-calorie-adjustment$0.002Developer Utilities
Max heart rate Tanaka calculator
208 − 0.7×age, free online
POST /health/hrmax-tanaka$0.002Developer Utilities
Ideal body weight calculator
Devine formula from height & sex, free
POST /health/ibw-devine$0.002Developer Utilities
Ideal body weight Miller calculator
IBW from height and sex
POST /health/ibw-miller$0.002Developer Utilities
Lean body mass Hume calculator
LBM from weight, height & sex, free
POST /health/lean-mass-hume$0.002Developer Utilities
MET-minutes per week calculator
intensity, duration and frequency
POST /health/met-minutes$0.002Developer Utilities
NEAT calculator
non-exercise thermogenesis from steps and weight
POST /health/neat-energy$0.002Developer Utilities
Normalized power calculator
cycling NP from a power series, free
POST /health/normalized-power$0.002Developer Utilities
Epley one-rep max calculator
1RM from weight and reps
POST /health/one-rep-max-epley$0.002Developer Utilities
One-rep max O'Conner calculator
1RM from weight and reps
POST /health/one-rep-max-oconner$0.002Developer Utilities
Physical activity level energy calculator
basal rate × WHO PAL
POST /health/pal-energy$0.002Developer Utilities
Barbell plate loading calculator
plates per side for a target weight
POST /health/plate-loading$0.002Developer Utilities
Protein intake by fitness goal calculator
daily grams from weight/goal
POST /health/protein-by-goal$0.002Developer Utilities
Reciprocal ponderal index calculator
height over cube root of weight
POST /health/reciprocal-ponderal-index$0.002Developer Utilities
Relative strength ratio calculator
lifted weight ÷ body weight, free
POST /health/relative-strength$0.002Developer Utilities
1RM percentage table calculator
training loads from one-rep max
POST /health/rep-max-percentage$0.002Developer Utilities
RER substrate calculator
carb and fat from measured RER
POST /health/rer-substrate$0.002Developer Utilities
RMR from fat-free mass calculator
Nelson equation for body composition
POST /health/rmr-from-ffm$0.002Developer Utilities
Schwartz-Malone coefficient calculator
relative strength from total
POST /health/schwartz-malone$0.002Developer Utilities
Skeletal muscle mass calculator
Lee equation from height & girths, free
POST /health/skeletal-muscle-mass$0.002Developer Utilities
Skinfold sum body density calculator
regression BD then fat %
POST /health/skinfold-body-density$0.002Developer Utilities
Daily sodium limit calculator
mg sodium and grams of table salt, free
POST /health/sodium-limit$0.002Developer Utilities
Steps per mile from stride calculator
treadmill & pedometer
POST /health/steps-per-mile-stride$0.002Developer Utilities
Swim pace yards to meters converter
SCY ↔ LCM pace with 0.9144 factor
POST /health/swim-pace-convert$0.002Developer Utilities
Cunningham TDEE calculator
BMR from lean mass times activity
POST /health/tdee-cunningham$0.002Developer Utilities
Thermic effect by macronutrient
TEF from protein carbs fat, free
POST /health/tef-by-macro$0.002Developer Utilities
VO2 reserve calculator
oxygen uptake reserve from max and rest
POST /health/vo2-reserve$0.002Developer Utilities
VO2 max from 5K race time calculator
velocity regression estimate
POST /health/vo2max-5k-race$0.002Developer Utilities
Astrand-Ryhming step test VO2 max calculator
free estimate
POST /health/vo2max-astrand-step$0.002Developer Utilities
VO2 max beep test calculator
level & shuttle shuttle-run estimate
POST /health/vo2max-beep-test$0.002Developer Utilities
VO2 max Bruce treadmill protocol calculator
free time estimate
POST /health/vo2max-bruce$0.002Developer Utilities
VO2 max Uth-Sørensen calculator
HRmax/HRrest ratio estimate, free
POST /health/vo2max-uth$0.002Developer Utilities
YMCA 3-minute step test VO2 max calculator
free estimate
POST /health/vo2max-ymca-step$0.002Developer Utilities
Cycling power-to-weight ratio calculator
watts per kg (W/kg), free
POST /health/watts-per-kg$0.002Developer Utilities
Wilks 2020 coefficient calculator
powerlifting relative strength score
POST /health/wilks2-coefficient$0.002Developer Utilities
Moles of element in compound calculator
n × subscript, free
POST /chem/moles-of-element-in-compound$0.002Developer Utilities
Moles to particles calculator
n × Avogadro number, free
POST /chem/moles-to-particles$0.002Developer Utilities
Tonicity osmolarity ratio calculator
classify vs plasma free
POST /chem/tonicity-ratio$0.002Developer Utilities
Trouton's rule calculator
estimate ΔH_vap from boiling point, free
POST /chem/trouton-rule$0.002Developer Utilities
Absolute neutrophil count calculator
ANC from WBC and %
POST /health/absolute-neutrophil$0.002Developer Utilities
Alcohol calorie calculator
volume, ABV & residual sugar
POST /health/alcohol-calories$0.002Developer Utilities
Anion gap delta ratio calculator
mixed acid-base assessment
POST /health/anion-gap-delta$0.002Developer Utilities
APRI calculator
AST to platelet ratio for liver fibrosis, free
POST /health/apri$0.002Developer Utilities
BUN to creatinine ratio calculator
serum BUN/Cr free
POST /health/bun-creatinine-ratio$0.002