An RGB color describes a color as a mix of red, green, and blue — each a number from 0 to 255. A HEX color code is the exact same information written as a compact 6-character string like #FF5733. Both formats cover the same 16.7 million colors — only the notation differs. The free NextUtils Color Converter converts between RGB, HEX, HSL, and CMYK instantly in your browser.
This guide explains what RGB and HEX mean, how the conversion works mathematically, where each format belongs in web design workflows, and how to convert either way in seconds — with or without a tool.
What is RGB?
RGB stands for Red, Green, Blue — an additive color model that mirrors how screens produce color. Every pixel on your monitor mixes three tiny light sources (red, green, blue) at varying intensities to create the color you see.
Each channel is a whole number between 0 (no light) and 255 (full intensity). Some examples:
| Color | RGB value | What it means |
|---|---|---|
| White | rgb(255, 255, 255) | All channels at maximum |
| Black | rgb(0, 0, 0) | All channels at zero |
| Pure red | rgb(255, 0, 0) | Only red channel active |
| Tomato orange | rgb(255, 87, 51) | High red, some green, low blue |
| Sky blue | rgb(135, 206, 235) | Low red, high green, high blue |
What is a HEX color code?
A HEX (hexadecimal) color code is a # followed by six characters — two for each RGB channel — written in base-16. Base-16 uses the digits 0–9 plus the letters A–F, so each pair can represent 256 values (00 to FF) using just two characters.
# FF5733→ R=255 · G=87 · B=51 → tomato orange
HEX codes are the most common color format in HTML and CSS. Every design tool — Figma, Sketch, Adobe XD — displays colors in HEX by default because the format is compact and universally understood across browsers, design systems, and style guides.
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RGB vs HEX — key differences
The two formats encode exactly the same color information. The differences are purely about notation, readability, and where each fits in a workflow:
| Factor | RGB | HEX |
|---|---|---|
| Syntax | rgb(255, 87, 51) | #FF5733 |
| Number base | Decimal (0–255) | Hexadecimal (00–FF) |
| Character length | Variable (10–18 chars) | Always 7 chars (#RRGGBB) |
| Opacity support | rgba(R, G, B, 0–1) | #RRGGBBAA (8-digit, CSS4) |
| Common in | CSS, canvas API, WebGL, image editors | HTML attributes, CSS, design tools, tokens |
| Beginner readability | ✅ Easier — decimal values are intuitive | Harder to decode mentally |
| Compact for stylesheets | More verbose | ✅ Shorter — less visual noise in CSS |
How to convert RGB to HEX manually
Converting RGB to HEX is a three-step process — one step per channel:
Take each channel value (0–255)
Start with your three decimal numbers. Example: rgb(255, 87, 51) → R = 255, G = 87, B = 51.
Convert each to base-16
Divide the decimal by 16. The quotient gives the first hex digit, the remainder gives the second. Or use any calculator in hex mode — 255 → FF, 87 → 57, 51 → 33.
Pad to two characters and concatenate
Each channel must be exactly two hex digits. If the result is a single digit, prefix it with 0 (e.g. 10 decimal → 0A hex). Combine with a # prefix: #FF5733.
Worked example — rgb(34, 197, 94)
R: 34 ÷ 16 = 2 remainder 2 → 22
G: 197 ÷ 16 = 12 remainder 5 → 12=C, 5=5 → C5
B: 94 ÷ 16 = 5 remainder 14 → 14=E → 5E
rgb(34, 197, 94) → #22C55E
This is Tailwind's green-500 — the math checks out every time.
To go the other way (HEX → RGB), split the code into three pairs and convert each from hex to decimal: #22C55E → 22=34, C5=197, 5E=94 → rgb(34, 197, 94).
In JavaScript you can do this in one line: parseInt('22C55E'.substring(0, 2), 16) // → 34
How to convert RGB to HEX with an online tool
Manual conversion works fine for one or two colors, but a color converter tool is faster for design work where you're converting dozens of values from a Figma file or a design system token file:
Open the Color Converter
Go to nextutils.com/tools/converters/color — no sign-up, no install. The tool loads in your browser immediately.
Enter your RGB values
Type the R, G, and B values (each 0–255) into the RGB input fields. The conversion updates in real time as you type.
Copy the HEX result
The HEX output (and HSL and CMYK equivalents) appear instantly. Click the copy icon to put the HEX code on your clipboard.
Paste into your stylesheet or design tool
Drop the copied HEX directly into a CSS file, Tailwind config, Figma color style, or anywhere else that accepts hex codes.
Convert RGB to HEX now — free, instant, no sign-up
Also converts to HSL and CMYK simultaneously. Includes WCAG contrast checking.
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Use cases in web design and CSS
Understanding when to reach for each format makes your CSS cleaner and your handoff with designers smoother:
CSS color properties
Both HEX and RGB work in color, background-color, border, outline, and box-shadow. HEX is shorter; use rgba() when you need transparency.
Design system tokens
Brand style guides and design tokens typically store colors as HEX. When converting a Figma design to code, HEX is the format you'll copy most.
Canvas and WebGL
The HTML5 Canvas API and WebGL expect numeric RGB values (or normalized 0–1 floats for WebGL). RGB is more natural here than parsing hex strings.
Tailwind CSS
Tailwind's default palette uses HEX internally, and custom theme colors in tailwind.config.js are also specified as hex strings.
CSS variables
When using CSS custom properties for theming, both work. However, separating channels (--color-primary-r: 34;) in RGB lets you apply dynamic opacity without recalculating the hex.
Accessibility checks
WCAG contrast ratio calculations work on raw RGB values. Converters that show RGB alongside HEX make it easy to plug values into a contrast checker without a second step.
Why use the NextUtils Color Converter?
Most online color converters handle only one direction. The NextUtils Color Converter converts all four major formats simultaneously — saving multiple round trips:
All formats at once
Enter any value in RGB, HEX, HSL, or CMYK — all four outputs update simultaneously.
Visual color preview
A live color swatch updates as you type so you can confirm you have the right color before copying.
WCAG contrast check
Instantly see whether your foreground/background pair passes AA or AAA contrast requirements — no separate tool needed.
One-click copy
Each format has its own copy button — click once to put the value on your clipboard, no selecting text.
Browser-only, no sign-up
Everything runs client-side. No data is sent to a server — safe for unreleased brand colors and internal design systems.
Real-time updates
Results update as you type, not after clicking a button. Useful for iterating on shades quickly.
Related color and design tools
Color Converter
Convert between RGB, HEX, HSL, and CMYK simultaneously. Includes live preview and WCAG contrast check.
Color Contrast Checker
Check whether a foreground/background color pair meets WCAG AA or AAA accessibility contrast requirements.
Color Palette Generator
Generate complementary, analogous, or triadic palettes from a base color — export as HEX, RGB, or Tailwind tokens.
CSS Gradient Generator
Build linear and radial CSS gradients visually. Uses HEX color stops — convert your RGB values first, then build your gradient.
Frequently asked questions
What is RGB color?
RGB stands for Red, Green, Blue — an additive color model used by screens. Each channel is a number from 0 (none) to 255 (full intensity), and the three values together define any of 16.7 million colors. In CSS it is written as rgb(255, 87, 51). When you add opacity it becomes rgba(255, 87, 51, 0.5).
What is a HEX color code?
A HEX color code is a # followed by six hexadecimal characters representing the same red, green, and blue channels as RGB — two characters each, in the format #RRGGBB. For example, #FF5733 means R=255, G=87, B=51. HEX is the standard format in HTML and CSS and is what design tools like Figma export by default.
How do I convert RGB to HEX?
Convert each channel (R, G, B) from decimal to a 2-digit hexadecimal value and concatenate them with a # prefix. Example: rgb(34, 197, 94) → R=34→22, G=197→C5, B=94→5E → #22C55E. To skip the math, use the free NextUtils Color Converter — type any RGB value and the HEX output appears instantly.
Is HEX the same as RGB?
Yes — HEX and RGB encode the same information. HEX is simply the hexadecimal representation of the same three decimal channel values. There is no loss of information when converting between them. Both formats describe the same 16,777,216 possible colors and are both fully supported in all modern browsers.
When should I use RGB instead of HEX in CSS?
Use RGB (or rgba) when you need to set opacity without writing an 8-digit hex, or when you are manipulating channel values in JavaScript. Use HEX for static colors in stylesheets — it is shorter and universally understood by browsers, preprocessors, and design tools. For new projects, CSS oklch() is worth considering for perceptually uniform color manipulation.
Convert any color format — free, instant, private
RGB ↔ HEX ↔ HSL ↔ CMYK. Live preview, WCAG contrast check, one-click copy. Everything runs in your browser — no upload, no account.
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