How do I convert RGB to HEX by hand?

Convert each channel (0–255) to a two-digit base-16 number and join them. rgb(30, 144, 255) becomes 1E, 90 and FF, so the HEX code is #1E90FF.

How is alpha converted?

Alpha from 0 to 1 is multiplied by 255 and written as two more hex digits. An alpha of 0.5 becomes 80, so rgba(30, 144, 255, 0.5) is #1E90FF80.

Why does the converter reject 256 or negative values?

Each RGB channel is one byte, so it must be between 0 and 255. Instead of silently clamping a typo to a different color, the converter tells you which value is out of range.

Yes. CSS allows fractional RGB values, so the converter accepts them and rounds to the nearest whole number for the HEX code.

RGB to HEX Converter

Enter RGB values or paste an rgb() color to get its HEX code.

RGB values (0–255) and alpha (0–1)

…or paste a CSS value

rgb(30, 144, 255), rgba(30, 144, 255, 0.5) or rgb(30 144 255 / 50%)

#1E90FF

HEX: #1E90FF
CSS: rgb(30, 144, 255)

Need the reverse? Use the HEX to RGB converter.

How to convert RGB to HEX

Enter red, green and blue values from 0 to 255 — or paste an rgb() or rgba() value.
Set alpha below 1 if the color should be transparent.
Copy the 6-digit HEX code, the 8-digit version with alpha, or the short form when there is one.

How the conversion works

Each channel is written as a two-digit hexadecimal number (00–FF) and the three are joined after a #. Numbers below 16 get a leading zero, so 9 becomes 09.

rgb(46, 139, 87) → #2E8B57

46  → 2 × 16 + 14 → 2E
139 → 8 × 16 + 11 → 8B
87  → 5 × 16 + 7  → 57

Alpha is scaled from 0–1 to 0–255 and added as a fourth pair. When every pair has two identical digits, CSS also accepts a short form: #FFCC00 can be written #FC0.

Features

Number fields with validation: values outside 0–255 are reported, not clamped.
Paste CSS values in comma or space syntax, including percentages.
6-digit, 8-digit (with alpha) and short HEX output with a live preview.

RGB to HEX examples

RGB and RGBA values with their HEX codes
Swatch	HEX	RGB / RGBA
	#FFFFFF	rgb(255, 255, 255)
	#000000	rgb(0, 0, 0)
	#FF6347	rgb(255, 99, 71)
	#1E90FF	rgb(30, 144, 255)
	#2E8B57	rgb(46, 139, 87)
	#FFD700	rgb(255, 215, 0)
	#00000080	rgba(0, 0, 0, 0.5)
	#1E90FF40	rgba(30, 144, 255, 0.25)

Related color tools

Convert back with HEX to RGB, prepare colors for print with RGB to CMYK, or explore colors visually in the color picker.

Frequently asked questions

How do I convert RGB to HEX by hand?: Convert each channel (0–255) to a two-digit base-16 number and join them. rgb(30, 144, 255) becomes 1E, 90 and FF, so the HEX code is #1E90FF.
How is alpha converted?: Alpha from 0 to 1 is multiplied by 255 and written as two more hex digits. An alpha of 0.5 becomes 80, so rgba(30, 144, 255, 0.5) is #1E90FF80.
Why does the converter reject 256 or negative values?: Each RGB channel is one byte, so it must be between 0 and 255. Instead of silently clamping a typo to a different color, the converter tells you which value is out of range.
Can I use decimals?: Yes. CSS allows fractional RGB values, so the converter accepts them and rounds to the nearest whole number for the HEX code.