The calculations designers keep doing by hand.
Color conversion, proportional scaling, grids, picas, copyfitting and the characters everyone gets wrong. Free, instant, and none of it leaves your browser.
Color Tools
Six tools that all work in OKLCH under the hood. That matters more than it sounds: OKLCH is perceptually uniform, so a midpoint looks like a midpoint and a hue rotation keeps every color at the same visual weight. Tools built on HSL and raw hex cannot do either, which is why their gradients go muddy and their palettes have one color that jumps out.
- Color ConverterEvery format for one color, including OKLCH.
- Contrast CheckerFive WCAG checks with a live preview of the actual text.
- Color Blend GeneratorSmooth ramps between two colors that keep their saturation.
- CSS Gradient GeneratorCSS gradients in both spaces, shown side by side.
- Color Palette GeneratorTints, shades and harmonies that hold together.
- Color Blindness SimulatorHow your color pair reads to everyone else.
Layout & Measurement Tools
The calculations that used to live on a wheel in a desk drawer, or on a laminated card pinned above the desk. Proportional scaling, picas to millimeters, how much space a given amount of copy will take, and where the columns fall on the page. None of them are difficult; all of them are tedious, and all of them are easy to get subtly wrong at eleven at night.
- Fraction and Unit ConverterDecimals to fractions, and every typographic unit.
- Proportional Scale CalculatorThe percentage, the new size, and whether it crops.
- Page Grid CalculatorColumns, margins and baselines, drawn to scale.
- Copyfitting CalculatorHow deep your copy runs, and whether the measure works.
- Special Character ReferenceSeventy characters, and when to use each.
- Device Screen SizesPoints, device pixels and scale factors, kept straight.
Print Production Tools
The calculations that sit between a finished design and a printed object. None of them are difficult and all of them are unforgiving: a spine two millimeters out is a reprint, a page count that does not fill its signatures is paper you paid for and threw away, and an image placed at half the resolution its screen needs looks soft in a way no amount of sharpening recovers.
- Halftone Screen CalculatorWhat resolution a line screen actually needs.
- Book Spine Width CalculatorSpine width from page count and paper, honestly.
- Imposition & Signature CalculatorSignatures, blanks and which pages print together.
- Paper & Envelope SizesEvery A, B, C, US and envelope size, and what fits what.
Built the way the work is actually made.
Perceptual color throughout
Every blend, palette and gradient is computed in OKLCH. That is why the middle of a gradient here does not turn to mud, and why a harmony set does not have one color that glares.
Honest about its limits
CMYK without a profile is an approximation and says so. A copyfit is an estimate and says so. A tool that hides its assumptions is harder to trust, not easier.
Nothing leaves the browser
No account, no analytics, no server. Every calculation runs on your machine, which is the only version of privacy that means anything.