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
Pregnancy weight gain calculator
BMI and weeks range, free
POST /health/pregnancy-weight-gain$0.002Developer Utilities
Daily protein intake calculator
grams from weight and g/kg target, free
POST /health/protein-intake$0.002Developer Utilities
Riegel race time predictor
predict finish times from a known race
POST /health/race-time-predictor$0.002Developer Utilities
Running calorie calculator
calories burned from distance, weight & grade
POST /health/running-calories$0.002Developer Utilities
Running pace calculator
min/km and min/mile from distance & time
POST /health/running-pace$0.002Developer Utilities
Steps to distance calculator
convert steps to km, miles, free
POST /health/steps-to-distance$0.002Developer Utilities
Swimming pace calculator
pace per 100m and 100 yards from distance & time
POST /health/swim-pace$0.002Developer Utilities
Target heart rate Karvonen calculator
reserve method, free
POST /health/target-hr-karvonen$0.002Developer Utilities
VO2 max Cooper test calculator
12-min distance estimate, free
POST /health/vo2max-cooper$0.002Developer Utilities
Waist-to-height ratio calculator
WHtR and risk category, free
POST /health/waist-height-ratio$0.002Developer Utilities
Waist-to-hip ratio calculator
WHR and health-risk band, free
POST /health/waist-hip-ratio$0.002Developer Utilities
BPM to milliseconds calculator
note durations & delay times, free
POST /hobby/bpm-to-ms$0.002Developer Utilities
Cents between frequencies calculator
musical interval in cents, free
POST /hobby/cents-interval$0.002Developer Utilities
Chord note calculator
notes and intervals from root and quality
POST /hobby/chord-notes$0.002Developer Utilities
Crop factor calculator
full-frame equivalent focal length & aperture, free
POST /hobby/crop-factor$0.002Developer Utilities
Depth of field calculator
near, far & total DOF, free
POST /hobby/depth-of-field$0.002Developer Utilities
Equivalent exposure calculator
match aperture, shutter & ISO, free
POST /hobby/equivalent-exposure$0.002Developer Utilities
Exposure value calculator
EV from aperture, shutter, ISO
POST /hobby/exposure-value$0.002Developer Utilities
Camera field of view calculator
AOV from focal length & sensor
POST /hobby/field-of-view$0.002Developer Utilities
Golden ratio font size calculator
heading & body type scale, free
POST /hobby/golden-ratio-type$0.002Developer Utilities
Knitting gauge calculator
cast on stitches & rows, free
POST /hobby/knitting-gauge$0.002Developer Utilities
Modular type scale generator
base, ratio & steps, free
POST /hobby/modular-scale$0.002Developer Utilities
Musical interval calculator
semitones and interval name from two notes, free
POST /hobby/musical-interval$0.002Developer Utilities
Note frequency calculator
equal temperament Hz from A4
POST /hobby/note-frequency$0.002Developer Utilities
NPF rule calculator
sharper max shutter for stars, free
POST /hobby/npf-rule$0.002Developer Utilities
Poker outs and odds calculator
next card and river hit probability, free
POST /hobby/poker-odds$0.002Developer Utilities
Print size & DPI calculator
pixels to inches, free
POST /hobby/print-dpi$0.002Developer Utilities
Reading time estimator
word count and WPM to duration, free
POST /hobby/reading-time$0.002Developer Utilities
Epoxy resin mix calculator
resin & hardener amounts by ratio, free
POST /hobby/resin-mix$0.002Developer Utilities
Musical scale generator
notes from root and scale type, free
POST /hobby/scale-notes$0.002Developer Utilities
Music transposition calculator
notes and chords by semitones
POST /hobby/transpose$0.002Developer Utilities
Yarn weight substitution calculator
skeins to buy from yardage, free
POST /hobby/yarn-substitution$0.002Developer Utilities
Air conditioner BTU calculator
room cooling capacity, free
POST /home/ac-btu$0.002Developer Utilities
Concrete block calculator
blocks from wall area, face size and waste
POST /home/blocks$0.002Developer Utilities
Carpet calculator
linear metres and area from room size and roll width free
POST /home/carpet$0.002Developer Utilities
Concrete column calculator
cylindrical volume from diameter, height and count
POST /home/concrete-column$0.002Developer Utilities
Concrete footing calculator
volume from L×W×D×count, free
POST /home/concrete-footing$0.002Developer Utilities
Concrete slab calculator
volume and bags from length, width, thickness free
POST /home/concrete-slab$0.002Developer Utilities
Crown molding calculator
sticks from perimeter and waste, free
POST /home/crown-molding$0.002Developer Utilities
Deck board calculator
boards needed from area, size, gap and waste free
POST /home/deck-boards$0.002Developer Utilities
Fence post calculator
posts and rails from length and spacing, free
POST /home/fence-posts$0.002Developer Utilities
Lawn fertilizer calculator
pounds to apply from area, N rate, and bag nitrogen % free
POST /home/fertilizer$0.002Developer Utilities
Floor tile calculator
tiles and boxes from room area, size and waste free
POST /home/floor-tiles$0.002Developer Utilities
Gravel calculator
volume and weight from area, depth and density, free
POST /home/gravel$0.002Developer Utilities
Heater BTU calculator
room volume, insulation and temperature rise free
POST /home/heater-btu$0.002Developer Utilities
Insulation R-value calculator
total assembly R and U-factor from layers
POST /home/insulation$0.002Developer Utilities
Laminate flooring calculator
packs from room area, coverage and waste
POST /home/laminate-flooring$0.002Developer Utilities
Mortar calculator
volume and bags from brick or block count free
POST /home/mortar$0.002Developer Utilities
Paver calculator
patio pavers needed from area, size and waste free
POST /home/pavers$0.002Developer Utilities
Pool chlorine dosage calculator
dose from volume, free chlorine levels, and product strength free
POST /home/pool-chlorine$0.002Developer Utilities
Swimming pool volume calculator
liters and gallons from shape and dimensions
POST /home/pool-volume$0.002Developer Utilities
Roof pitch calculator
rise, run, slope angle and rafter factor, free
POST /home/roof-pitch$0.002Developer Utilities
Roofing shingles calculator
bundles and squares from area and pitch free
POST /home/roof-shingles$0.002Developer Utilities
Sand calculator
volume and weight from area, depth and density
POST /home/sand$0.002Developer Utilities
Staircase step calculator
riser count, exact riser and tread run
POST /home/staircase-steps$0.002Developer Utilities
Topsoil calculator
volume in cubic yards and cubic meters from area and depth free
POST /home/topsoil$0.002Developer Utilities
Wall stud calculator
count studs from length, spacing and openings
POST /home/wall-studs$0.002Developer Utilities
Wall tile calculator
tiles and boxes from area, size and waste
POST /home/wall-tiles$0.002Developer Utilities
Wallpaper rolls calculator
pattern repeat included, free
POST /home/wallpaper-rolls$0.002Developer Utilities
Water tank volume calculator
capacity in liters and gallons at a fill depth, free
POST /home/water-tank-volume$0.002