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Colour instrument

RGB565 Colour Reference

Pick an ordinary RGB colour and get its TFT-friendly RGB565 value, reproduced colour and ready-to-paste Arduino constant.

Format
Interactive
Published
Updated

Live conversion

Pick a colour

Choose an ordinary 24-bit colour. The nearest RGB565 value and the colour a 16-bit display can actually reproduce update immediately.

RGB565 display colour
Hex
0xF267
Decimal
62055
16-bit binary
11110 010011 00111
Stored channels
R 30 · G 19 · B 7
Reproduced RGB
247, 77, 58

Ready to paste

constexpr uint16_t COLOUR = 0xF267;

If you have ever bounced between an ordinary RGB colour picker and a tiny TFT library demanding 0xF81F as though that is a perfectly ordinary thing to ask, this is the bridge between them.

What RGB565 stores

RGB565 stores colour in 16 bits:

  • 5 bits red
  • 6 bits green
  • 5 bits blue

Green gets the extra bit because human vision is more sensitive to changes in green. Red and blue each get 32 possible levels; green gets 64. Converting from 24-bit RGB therefore loses some precision, which is why the picker shows the reproduced colour alongside the source.

The conversion

From 8-bit RGB values:

rgb565 = ((red & 0xF8) << 8) | ((green & 0xFC) << 3) | (blue >> 3)

Or, if you prefer to think in ranges:

  • red: 0-255 becomes 0-31
  • green: 0-255 becomes 0-63
  • blue: 0-255 becomes 0-31

Useful fixed values

Black   0x0000
White   0xFFFF
Red     0xF800
Green   0x07E0
Blue    0x001F
Yellow  0xFFE0
Cyan    0x07FF
Magenta 0xF81F

Where it helps

  • hard-coding UI colours for TFT displays
  • comparing the selected colour with what the display can reproduce
  • pasting a uint16_t constant directly into Arduino code