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
Gradient magnitude calculator
||∇f|| from ∂f/∂x and ∂f/∂y
POST /calculus/gradient-magnitude$0.002Developer Utilities
Hessian determinant calculator
apply the second derivative test
POST /calculus/hessian-determinant$0.002Developer Utilities
Normal line to surface calculator
parametric line from gradient, free
POST /calculus/normal-line-surface$0.002Developer Utilities
Numerical Partial Derivative with Respect to x Calculator
POST /calculus/partial-derivative-x-numeric$0.002Developer Utilities
RGB to XYZ converter
sRGB to CIE 1931 XYZ (D65), free
POST /color/rgb-xyz$0.002Developer Utilities
LAB to RGB converter
CIE L*a*b* to sRGB channels (D65), free
POST /color/lab-rgb$0.002Developer Utilities
RGB to LCH converter
sRGB channels to CIE L*C*h° (D65), free
POST /color/rgb-lch$0.002Developer Utilities
RGB to OKLCH converter
perceptual lightness, chroma and hue
POST /color/rgb-oklch$0.002Developer Utilities
RGB to YUV converter
BT.601 luminance and chrominance, free
POST /color/rgb-yuv$0.002Developer Utilities
YIQ to RGB converter
convert NTSC luminance and chrominance
POST /color/yiq-rgb$0.002Developer Utilities
CMYK to HSV converter
print ink to hue and value
POST /color/cmyk-hsv$0.002Developer Utilities
HSV to HSL converter
hue, saturation, value to lightness free
POST /color/hsv-hsl$0.002Developer Utilities
HWB to HSL converter
hue, saturation and lightness
POST /color/hwb-hsl$0.002Developer Utilities
RGB to LUV converter
sRGB channels to CIE L*u*v* (D65), free
POST /color/rgb-luv$0.002Developer Utilities
XYZ to xyY converter
CIE chromaticity and luminance
POST /color/xyz-xyy$0.002Developer Utilities
Expand shorthand hex color
#RGB to #RRGGBB free
POST /color/hex3-hex6$0.002Developer Utilities
Hex8 to RGBA converter
parse #RRGGBBAA color channels
POST /color/hex8-rgba$0.002Developer Utilities
Hex to CMYK converter
#RRGGBB to cyan magenta yellow key, free
POST /color/hex-cmyk$0.002Developer Utilities
LAB to hex converter
CIE L*a*b* to sRGB hex, free
POST /color/lab-hex$0.002Developer Utilities
OKLCH to hex converter
accurate sRGB color conversion
POST /color/oklch-hex$0.002Developer Utilities
RGB555 to RGB Unpacker
Convert 15-Bit Color to 8-Bit Channels
POST /color/rgb555-rgb$0.002Developer Utilities
XYZ to hex converter
CIE XYZ tristimulus to #RRGGBB sRGB, free
POST /color/xyz-hex$0.002Developer Utilities
Darken hex color by percent
HSL lightness, free online
POST /color/darken-percent$0.002Developer Utilities
Dim a color by reducing HSV value
deterministic color tool
POST /color/dim-hsv$0.002Developer Utilities
Apply gamma correction to a color
RGB power curve, free
POST /color/gamma$0.002Developer Utilities
Hex to grayscale by Rec. 709 luminance
POST /color/grayscale-luminance$0.002Developer Utilities
Blend two colors by ratio
weighted RGB color calculator
POST /color/mix-ratio$0.002Developer Utilities
RGB565 to RGB unpacker
convert 16-bit color to 8-bit RGB
POST /color/rgb565-rgb$0.002Developer Utilities
RGB to color temperature
estimate Kelvin CCT from sRGB, free
POST /color/rgb-kelvin$0.002Developer Utilities
Clamp color to gamut
fix RGB values to the 0–255 range
POST /color/clamp-gamut$0.002Developer Utilities
Color Burn Blend Two Colors
Hex and RGB Result
POST /color/color-burn$0.002Developer Utilities
Hex to grayscale by lightness
HSL (max+min)/2 gray hex, free
POST /color/grayscale-lightness$0.002Developer Utilities
Subtractive color mixer
blend two colours like paint (RYB), free
POST /color/mix-subtractive$0.002Developer Utilities
Overlay blend two colors
deterministic hex calculator
POST /color/overlay$0.002Developer Utilities
Shift color temperature warmer or cooler
hex color tool
POST /color/temperature-shift$0.002Developer Utilities
Unpremultiply RGBA Alpha
Recover Straight Color Channels
POST /color/unpremultiply$0.002Developer Utilities
Darken blend two colors
min RGB channels, free
POST /color/darken-only$0.002Developer Utilities
Exclusion blend two colors
calculate the resulting hex color
POST /color/exclusion$0.002Developer Utilities
Pin light blend
combine two colors (darken or lighten by top)
POST /color/pin-light$0.002Developer Utilities
Square color scheme generator
four balanced colors from one hex
POST /color/square-scheme$0.002Developer Utilities
Generate color tints
create an even palette toward white
POST /color/tints-palette$0.002Developer Utilities
APCA contrast calculator
Lc between text and background
POST /color/apca-contrast$0.002Developer Utilities
W3C brightness difference calculator
test two colors
POST /color/brightness-diff-w3c$0.002Developer Utilities
CIE94 color difference calculator
Delta E 1994
POST /color/delta-e-94$0.002Developer Utilities
Evenly spaced hue palette
N colors around the wheel, free
POST /color/hue-wheel$0.002Developer Utilities
Relative luminance calculator
WCAG sRGB formula, free
POST /color/relative-luminance$0.002Developer Utilities
Simulate protanomaly color
reduced red sensitivity filter for hex/RGB
POST /color/sim-protanomaly$0.002Developer Utilities
Protanopia color simulator
Brettel-Vienot matrix
POST /color/sim-protanopia$0.002Developer Utilities
Warm and cool color variant palette generator
POST /color/temperature-palette$0.002Developer Utilities
Contrast ratio letter grade
WCAG pair scored A to fail
POST /color/contrast-grade$0.002Developer Utilities
Gradient color stops generator
evenly space colors
POST /color/gradient-stops$0.002Developer Utilities
Hex alpha to opacity percent
convert #RRGGBBAA transparency
POST /color/hex-alpha-to-opacity$0.002Developer Utilities
HSL to CSS string formatter
create a valid hsl() color
POST /color/hsl-to-css$0.002Developer Utilities
Interpolate two colors in HSL
shortest hue path blender
POST /color/interpolate-hsl$0.002Developer Utilities
OKLCH to CSS string
format valid oklch() colors, free
POST /color/oklch-to-css$0.002Developer Utilities
Color swatch SVG generator
inline hex rectangle markup, free
POST /color/swatch-svg$0.002Developer Utilities
Cubic-bezier color interpolation
eased RGB color at any fraction
POST /color/bezier-interpolate$0.002Developer Utilities
Rich black recipe generator
CMYK under full black for press
POST /color/black-generation$0.002Developer Utilities
Halftone tint to gray calculator
include dot gain
POST /color/halftone-gray$0.002Developer Utilities
Hex to CMYK ink percentages
#RRGGBB to print channels, free
POST /color/hex-to-ink-channels$0.002