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
Caffeine half-life decay calculator
remaining mg after hours
POST /health/caffeine-decay$0.002Developer Utilities
Conception window calculator
fertile dates from last period
POST /health/conception-window$0.002Developer Utilities
Due date Naegele rule calculator
LMP to estimated delivery date
POST /health/due-date-naegele$0.002Developer Utilities
Estimated fetal weight calculator
Hadlock biometry, free
POST /health/efw-hadlock$0.002Developer Utilities
eGFR CKD-EPI 2009 calculator
classic creatinine equation free
POST /health/egfr-ckd-epi-2009$0.002Developer Utilities
eGFR cystatin C calculator
CKD-EPI equation free
POST /health/egfr-cystatin$0.002Developer Utilities
Fractional excretion of urea calculator
FEUrea free
POST /health/feurea$0.002Developer Utilities
Gestational age from due date calculator
weeks + days from EDD
POST /health/gestational-age-edd$0.002Developer Utilities
Calories to kilojoules converter
kcal to kJ food energy, free
POST /health/kcal-to-kj$0.002Developer Utilities
Keto carb limit calculator
max daily net carbs, free
POST /health/keto-carb-limit$0.002Developer Utilities
Modified shock index calculator
HR ÷ MAP, free offline
POST /health/modified-shock-index$0.002Developer Utilities
Net carbs calculator
total carbs minus fiber and sugar alcohols
POST /health/net-carbs$0.002Developer Utilities
Non-HDL cholesterol calculator
total minus HDL free
POST /health/non-hdl-cholesterol$0.002Developer Utilities
QTc Hodges calculator
corrected QT from QT and heart rate
POST /health/qtc-hodges$0.002Developer Utilities
Recipe portion scaler
scale ingredients for a new serving count
POST /health/recipe-portion-scaler$0.002Developer Utilities
Calendar method safe days calculator
Standard Days fertility window
POST /health/safe-days-calendar$0.002Developer Utilities
Sleep cycle bedtime calculator
bedtimes from wake time in 90-min cycles
POST /health/sleep-cycles-bedtime$0.002Developer Utilities
Sleep midpoint chronotype calculator
mid-sleep time from bedtime and wake
POST /health/sleep-midpoint$0.002Developer Utilities
Sweat rate calculator
from pre/post weight, fluid intake and duration
POST /health/sweat-rate$0.002Developer Utilities
Triglyceride-glucose (TyG) index calculator
insulin resistance marker
POST /health/tyg-index$0.002Developer Utilities
Attic insulation depth calculator
inches for a target R-value
POST /home/attic-insulation-depth$0.002Developer Utilities
Baseboard heater sizing calculator
wattage and length from room area
POST /home/baseboard-heater-sizing$0.002Developer Utilities
Block wall calculator
CMU blocks and mortar from wall area and face size
POST /home/block-wall$0.002Developer Utilities
Brick mortar bag calculator
bags of mix from brick count and coverage
POST /home/brick-mortar-bags$0.002Developer Utilities
Ceiling fan size calculator
blade span from room square footage
POST /home/ceiling-fan-size$0.002Developer Utilities
Chair rail calculator
linear feet and pieces from perimeter, free
POST /home/chair-rail$0.002Developer Utilities
CMU grout fill calculator
core volume from cells and wall height
POST /home/cmu-grout-fill$0.002Developer Utilities
Concrete countertop calculator
volume and bags from dimensions
POST /home/concrete-countertop$0.002Developer Utilities
Concrete mix ratio calculator
cement, sand & gravel by 1:2:3
POST /home/concrete-mix-ratio$0.002Developer Utilities
Concrete patio calculator
volume and bags from area and thickness free
POST /home/concrete-patio$0.002Developer Utilities
Concrete wall calculator
volume and bags from L×H×T free
POST /home/concrete-wall$0.002Developer Utilities
Concrete control joint calculator
spacing and total linear feet free
POST /home/control-joints$0.002Developer Utilities
Deck beam span calculator
allowable span from size, species & joist span
POST /home/deck-beam-span$0.002Developer Utilities
Deck stain calculator
gallons from deck area, railing and coverage free
POST /home/deck-stain$0.002Developer Utilities
Diagonal tile layout calculator
extra waste vs straight grid free
POST /home/diagonal-tile$0.002Developer Utilities
Downspout count calculator
gutters and roof drainage area
POST /home/downspout-count$0.002Developer Utilities
Drywall tape calculator
joint tape linear feet and rolls from sheets
POST /home/drywall-tape$0.002Developer Utilities
Drywall texture calculator
bags and gallons from spray area, free
POST /home/drywall-texture$0.002Developer Utilities
Duct size calculator
supply air from CFM and velocity, free
POST /home/duct-size$0.002Developer Utilities
Fascia board calculator
linear feet and boards from eave and rake
POST /home/fascia-length$0.002Developer Utilities
Floor joist calculator
count joists from room width and on-center spacing
POST /home/floor-joist-count$0.002Developer Utilities
Garage floor tile calculator
interlocking tiles from area, size and waste
POST /home/garage-floor-tiles$0.002Developer Utilities
Hardwood flooring calculator
sq ft and boxes with waste
POST /home/hardwood-floor$0.002Developer Utilities
Header length calculator
rough opening plus jack stud bearing
POST /home/header-length$0.002Developer Utilities
HVAC tonnage calculator
AC tons from sq ft and climate zone
POST /home/hvac-tonnage$0.002Developer Utilities
LVL beam ply calculator
estimate plies from span and load
POST /home/lvl-beam-plies$0.002Developer Utilities
Metal roof screw calculator
screws from panel area and batten spacing
POST /home/metal-roof-screws$0.002Developer Utilities
Mortar joint volume calculator
fill volume from unit size and joint width
POST /home/mortar-joint-volume$0.002Developer Utilities
Nominal to actual lumber size
2x4 true dimensions in inches
POST /home/nominal-actual-lumber$0.002Developer Utilities
Electrical panel load calculator
size main service amps
POST /home/panel-load$0.002Developer Utilities
Paver gravel base calculator
cubic yards from area and compacted depth
POST /home/paver-gravel-base$0.002Developer Utilities
Pergola lumber calculator
posts, beams and rafters from size and spacing
POST /home/pergola-lumber$0.002Developer Utilities
Picture rail calculator
linear feet from perimeter and doors, free
POST /home/picture-rail$0.002Developer Utilities
Popcorn ceiling area calculator
soak water for texture removal, free
POST /home/popcorn-ceiling$0.002Developer Utilities
Rafter count calculator
common rafters from ridge length and OC spacing
POST /home/rafter-count$0.002Developer Utilities
Rafter overhang length calculator
extra rafter from eave projection, free
POST /home/rafter-overhang$0.002Developer Utilities
Rebar weight calculator
total steel from length and unit weight per foot
POST /home/rebar-weight$0.002Developer Utilities
Roof batten calculator
linear feet and rows from area and spacing free
POST /home/roof-batten-count$0.002Developer Utilities
Roof dead load calculator
psf from roofing, sheathing and framing
POST /home/roof-dead-load$0.002Developer Utilities
Roof pitch multiplier calculator
slope area factor and roof angle
POST /home/roof-pitch-multiplier$0.002