Convert RGB color to hex

Convert an RGB color into the six-digit hexadecimal format used by CSS, design systems, graphics tools, and many data files. Enter red, green, and blue as whole numbers from 0 through 255, and the converter returns one uppercase code in #RRGGBB form. The calculation is deterministic and does not estimate, clamp, or silently repair invalid values.

Understand how RGB becomes a hexadecimal color

An RGB color stores three independent light intensities: red, green, and blue. Each channel can contain one of 256 integer values, starting at 0 and ending at 255. A six-digit hexadecimal color represents exactly the same information with two base-16 digits per channel.

The first pair belongs to red, the second pair belongs to green, and the final pair belongs to blue. Decimal 0 becomes 00, decimal 255 becomes FF, and values between them are converted and padded to two characters when necessary. For example, an input of red 255, green 128, and blue 0 produces #FF8000.

The leading hash identifies the value as a color in CSS and many design tools, while the six following characters preserve all three eight-bit channels without losing precision. This converter always returns the complete six-digit form, even when a shorter CSS notation could describe the same color. That fixed format is easier to compare, store, test, and pass between systems because every successful response has the same length and channel order.

Letter digits are returned in uppercase, but uppercase and lowercase hexadecimal codes describe the same color in CSS.

Provide valid channel values and interpret errors

Send an object containing r, g, and b, with each field set to a whole number between 0 and 255 inclusive. All three fields are required because omitting a channel would leave the color incomplete. Zero is valid and means that the corresponding primary contributes no light; 255 is also valid and means full intensity.

Values such as 12.5 are rejected because an eight-bit RGB channel in this contract must be an integer. Negative numbers and values above 255 are rejected rather than clamped. Clamping can conceal a broken sensor reading, spreadsheet formula, user interface control, or upstream validation rule, so a visible error is safer for automated work.

When a request fails, inspect the named channel, correct its source value, and submit the complete triple again. Because the algorithm has no network access, random behavior, or clock dependency, the same valid r, g, and b values always produce the same result in browser use, scripts, tests, and production jobs.

Use the result in design and development workflows

The returned code can be placed directly in CSS properties such as color, background-color, border-color, and fill. It also fits common design-token formats, theme configuration files, chart palettes, email templates, and documentation that records brand colors. Designers can convert channel values copied from an image editor before adding a swatch to a component library.

Developers can transform RGB columns from a database or spreadsheet into standardized strings before exporting a theme. Data pipelines benefit from strict errors because an invalid channel stops the conversion instead of introducing a plausible but incorrect color. For occasional work, the browser interface provides a fast way to check a triple without writing code.

Keep the leading hash when placing the result in CSS or a field that expects web color notation. If another system requests only six raw characters, remove the hash after conversion while leaving the channel pairs unchanged. This capability converts RGB integers only; it does not calculate transparency, color profiles, perceptual differences, HSL, CMYK, or nearest named colors, so use dedicated tools when those transformations are required.