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
Color lightener
lighten a hex color by percentage, free HSL tool
POST /color/lighten$0.002Developer Utilities
Color mixer
blend two hex colours by ratio, free
POST /color/mix$0.002Developer Utilities
CSS color name to hex
tomato, navy, rebeccapurple to #RRGGBB, free
POST /color/name-hex$0.002Developer Utilities
RGB to HSL converter
hue, saturation, lightness free
POST /color/rgb-hsl$0.002Developer Utilities
RGB to decimal integer
24-bit color pack free
POST /color/rgb-int$0.002Developer Utilities
Color shades generator
tints and shades by stepping HSL lightness, free
POST /color/shades$0.002Developer Utilities
Triadic color scheme generator
three hues at 120°, free
POST /color/triadic$0.002Developer Utilities
Combinations calculator
n choose r (binomial coefficient)
POST /combo/combinations$0.002Developer Utilities
Integer compositions calculator
ordered partitions into positive parts
POST /combo/compositions$0.002Developer Utilities
Derangement calculator
subfactorial !n, no fixed points
POST /combo/derangement$0.002Developer Utilities
Multinomial coefficient calculator
n! / (n1! n2! … nk!)
POST /combo/multinomial$0.002Developer Utilities
Integer partition calculator
p(n) ways to sum, free
POST /combo/partition-count$0.002Developer Utilities
Pascal's triangle generator
first n rows with exact BigInt entries
POST /combo/pascal-triangle$0.002Developer Utilities
Permutations calculator
P(n,r) = n!/(n−r)! with BigInt
POST /combo/permutations$0.002Developer Utilities
Permutations with repetition
n^r ordered selections, free
POST /combo/permutations-with-repetition$0.002Developer Utilities
Round-robin matches calculator
games and rounds for n teams
POST /combo/round-robin$0.002Developer Utilities
Stirling numbers of the second kind
S(n,k) partitions, free
POST /combo/stirling-second$0.002Developer Utilities
Acres to square meters converter
exact factor, free
POST /conv/acres-to-square-meters$0.002Developer Utilities
Physical action converter
J·s, eV·s, erg·s, h, ħ, free
POST /conv/action-physics$0.002Developer Utilities
Water alkalinity converter
mg/L CaCO3, meq/L, dKH, free
POST /conv/alkalinity$0.002Developer Utilities
Angular momentum converter
kg·m²/s, g·cm²/s, J·s, free
POST /conv/angular-momentum$0.002Developer Utilities
API gravity converter
°API, specific gravity and density, free
POST /conv/api-gravity$0.002Developer Utilities
ATM to PSI converter
exact atmosphere factor, free
POST /conv/atm-to-psi$0.002Developer Utilities
Beaufort scale converter
force, knots, mph, m/s, free
POST /conv/beaufort-wind$0.002Developer Utilities
Belt size converter
waist in/cm, numeric belt & letter, free
POST /conv/belt-size$0.002Developer Utilities
Binary prefix converter
kibi, mebi, gibi vs kilo, free
POST /conv/binary-prefix$0.002Developer Utilities
BTU to kWh converter
exact International Table factor, free
POST /conv/btu-to-kwh$0.002Developer Utilities
Calories to joules converter
exact 4.184 factor, free
POST /conv/calories-to-joules$0.002Developer Utilities
Calorific value converter
MJ/m³, BTU/ft³, kcal/L, free
POST /conv/calorific-value$0.002Developer Utilities
CM to inches converter
exact 2.54 factor, free
POST /conv/cm-to-inches$0.002Developer Utilities
Color depth converter
bpp, colors, bits/channel, free
POST /conv/color-depth$0.002Developer Utilities
Cubic meters to cubic feet converter
exact factor, free
POST /conv/cubic-meters-to-cubic-feet$0.002Developer Utilities
Degrees to gradians converter
exact deg × 10/9, free
POST /conv/degrees-to-gradians$0.002Developer Utilities
Didot point converter
cicero, mm and PostScript points, free
POST /conv/didot-point$0.002Developer Utilities
Electric flux converter
V·m, N·m²/C, C/ε₀, statV·cm, free
POST /conv/electric-flux$0.002Developer Utilities
Electron mobility converter
m²/(V·s), cm²/(V·s), free
POST /conv/electron-mobility$0.002Developer Utilities
Entropy converter
J/K, cal/K, BTU/R and more, free
POST /conv/entropy$0.002Developer Utilities
Equivalent weight converter
g/eq, kg/eq, mg/meq, free
POST /conv/equivalent-weight$0.002Developer Utilities
Fabric weight converter
gsm, oz/yd², oz/ft², free
POST /conv/fabric-weight$0.002Developer Utilities
Fahrenheit to Rankine converter
exact F+459.67, free
POST /conv/fahrenheit-to-rankine$0.002Developer Utilities
Film speed converter
ISO, ASA, DIN and more, free
POST /conv/film-speed$0.002Developer Utilities
Foot-pounds to newton-meters converter
exact factor, free
POST /conv/foot-pounds-to-newton-meters$0.002Developer Utilities
Gallons to cups converter
exact US factor, free
POST /conv/gallons-to-cups$0.002Developer Utilities
Gallons to quarts converter
exact US factor, free
POST /conv/gallons-to-quarts$0.002Developer Utilities
Glove size converter
cm, inches and numeric size, free
POST /conv/glove-size$0.002Developer Utilities
Hardness scale converter
Rockwell, Brinell, Vickers, free
POST /conv/hardness$0.002Developer Utilities
Hectares to acres converter
exact factor, free
POST /conv/hectares-to-acres$0.002Developer Utilities
Humidity ratio converter
kg/kg, grains/lb, g/kg and more, free
POST /conv/humidity-ratio$0.002Developer Utilities
Hydraulic conductivity converter
m/s, cm/h, gpd/ft², free
POST /conv/hydraulic-conductivity$0.002Developer Utilities
Imperial gallons to US gallons converter
exact factor, free
POST /conv/imperial-gallons-to-us-gallons$0.002Developer Utilities
Inches to cm converter
convert inches to centimeters, free
POST /conv/inches-to-cm$0.002Developer Utilities
Jerk converter
m/s³, ft/s³, g/s and more, free
POST /conv/jerk$0.002Developer Utilities
Joules to foot-pounds converter
exact factor, free
POST /conv/joules-to-foot-pounds$0.002Developer Utilities
kg/m³ to lb/ft³ converter
exact density factor, free
POST /conv/kg-per-m3-to-lb-per-ft3$0.002Developer Utilities
KG to stone converter
exact factor, free in browser
POST /conv/kg-to-stone$0.002Developer Utilities
KM to miles converter
exact factor, free in browser
POST /conv/km-to-miles$0.002Developer Utilities
Knots to km/h converter
exact 1.852 factor, free in browser
POST /conv/knots-to-kmh$0.002Developer Utilities
kW to hp converter
exact mechanical horsepower factor, free
POST /conv/kw-to-hp$0.002Developer Utilities
Lbs to ounces converter
exact 16 oz factor, free
POST /conv/lbs-to-ounces$0.002Developer Utilities
Vacuum leak rate converter
mbar·L/s, sccm, atm·cc/s, free
POST /conv/leak-rate$0.002