ToolZone
Professional utilities running entirely in your browser. Fast, private, and 100% free — no signup, no uploads.
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Short explainers for the problems people search before opening a tool.
Professional utilities running entirely in your browser. Fast, private, and 100% free — no signup, no uploads.
Short explainers for the problems people search before opening a tool.
ToolZone is a curated collection of 28 free online tools for developers, designers, writers, and everyday productivity. Every tool runs entirely in your browser — no signup, no uploads. Your tool input never leaves your device.
Format and validate JSON, generate strong passwords, encode and decode Base64 or URLs, test regular expressions, convert colors, build CSS gradients, calculate BMI or age, generate Lorem Ipsum, hash text with MD5 or SHA-256, and more — all from a single fast, private, dark-themed workspace.
Whether you're a developer needing quick utilities, a designer working with colors and gradients, or a writer counting words and characters, ToolZone gives you instant, low-clutter access to professional-grade web tools that work offline once loaded.
Pick a color visually or type a value in any format and see it converted to HEX, RGB, HSL and CMYK at the same time. Essential for web developers, print designers and anyone matching brand colors across screens and print.
A brand guideline specifies #2563EB. The design system, however, stores colours as HSL so that hover and disabled states can be derived by shifting lightness rather than hard-coding new hex values.
Converting once gives hsl(217 91% 60%). The team stores the three channels as a CSS custom property, then generates the hover state with a lightness of 52% and the muted state with a saturation of 40% — a consistent palette from a single source colour, and a dark-theme variant for free.
HEX is just a byte-per-channel notation for RGB: #2563EB is R=37, G=99, B=235. Parsing expands 3-digit shorthand, accepts an optional alpha pair, and validates the hex digits.
RGB to HSL finds the maximum and minimum channel values: lightness is their midpoint, saturation is their spread relative to that midpoint, and hue is the angle derived from which channel is largest. The conversion is lossless in both directions apart from rounding to whole percentages.
All maths runs in the page, so you can convert a client's confidential palette without uploading it anywhere.
Colour conversion options compared:
| Tool | How it works | Trade-off |
|---|---|---|
| Design tools (Figma, Photoshop) colour picker | Shows HEX/RGB/HSL for a selected swatch. | Requires the file and the app open; awkward for a value pasted from a ticket. |
| Browser devtools colour swatch | Shift-click a colour to cycle notations. | Only works on colours already present in the stylesheet. |
| ToolZone Color Converter | Paste any HEX, RGB or HSL value and get the others instantly with a live preview. | Converts values; it is not a palette designer. |
CMYK is for print (subtractive); HEX/RGB/HSL are for screens (additive). Without an ICC profile, conversion is approximate — always proof on real paper for print.
Both use hue and saturation, but HSL's lightness goes from black (0) through colour (50%) to white (100%); HSV's value goes from black (0) to colour (100%), with white added via saturation.