What is the difference between RGB and RGBA?

RGB defines red, green, and blue color channels with values from 0 to 255. RGBA adds a fourth alpha channel (0.0 to 1.0) that controls opacity — 0 is fully transparent and 1 is fully opaque.

Can I type values directly instead of using sliders?

Yes. You can type R, G, and B values in the number inputs. The sliders and inputs stay in sync automatically.

What happens if I enter a value outside 0–255?

The tool clamps any out-of-range value to the nearest valid boundary (0 or 255) and shows an inline warning so you know the value was adjusted.

Is there a keyboard-friendly way to fine-tune the alpha?

Yes. Click the alpha slider and use the arrow keys to increment or decrement the value in steps of 0.01.

Does this tool send my color data to a server?

No. All computation runs entirely in your browser. No data is transmitted anywhere.

Can I paste the output directly into CSS?

Yes. The output is a valid CSS rgba() function string — for example rgba(255, 87, 51, 0.75) — ready to paste into any stylesheet or design tool.

RGB to RGBA Converter

Enter R, G, B values, adjust the alpha slider, and get the rgba() CSS string instantly with a live preview.

RGB Input

Red (R)

Green (G)

Blue (B)

Alpha (Opacity) 0.75

0 — Transparent 1 — Opaque

Pick a color Sets R, G, B from picker

RGBA Output

rgba(255, 87, 51, 0.75)

255

0.75

Second row: rgb() without alpha, for reference

Summary

A free, browser-only tool that converts an RGB color to RGBA by appending an alpha (opacity) channel. Enter red, green, and blue values (0–255), drag the alpha slider (0.00–1.00), and get a valid CSS rgba() string you can copy directly into your stylesheet. A live checkerboard-backed swatch shows the true transparency effect.

How it works

Enter red, green, and blue channel values (0–255) in the input fields, or use the sliders.
Drag the Alpha slider to set opacity from 0.00 (fully transparent) to 1.00 (fully opaque).
The live color swatch updates instantly, showing the color over a checkerboard background to reveal transparency.
The rgba() CSS string is built and displayed in the output field.
Click Copy to copy the rgba() value to your clipboard.

Use cases

Convert brand RGB colors to semi-transparent overlays.
Generate CSS rgba() values for glassmorphism or frosted-glass effects.
Create translucent button backgrounds or card shadows.
Quickly prototype UI color schemes with adjustable opacity.
Build tooltip or modal backdrop colors with controlled transparency.

Frequently Asked Questions

Last updated: 2026-05-28 · Reviewed by Nham Vu