RGB555 to RGB Unpacker

The RGB555 to RGB unpacker converts one unsigned 15-bit packed color into separate red, green, and blue values suitable for modern 8-bit color workflows. It accepts either ordinary decimal text or hexadecimal text beginning with 0x, validates the complete input, extracts the three five-bit fields, and scales each field to the range from 0 through 255. The result also preserves the decoded five-bit components and a normalized hexadecimal representation, making the conversion easy to inspect, compare, test, or integrate into a data-processing pipeline.

Understand the RGB555 bit layout

RGB555 stores three color channels inside fifteen significant bits. In this unpacker, bits 14 through 10 hold red, bits 9 through 5 hold green, and bits 4 through 0 hold blue. Each field can therefore represent an integer from 0 through 31.

The accepted packed value is unsigned and must remain between 0 and 32767, inclusive; a sixteenth high bit is not treated as transparency, intensity, or padding. You may provide the value as decimal text, such as 31775, or as hexadecimal text with an explicit 0x prefix, such as 0x7C1F. The output includes a normalized four-digit hexadecimal form so that results are straightforward to compare with memory dumps and file-format documentation.

It also reports each original five-bit component alongside its expanded eight-bit channel. This makes the operation transparent: you can see both the exact stored field and the approximate display-oriented value derived from it, without needing to perform shifts or masks manually.

See how five bits become eight bits

After extraction, every five-bit component is scaled across the full eight-bit range with the formula round(component multiplied by 255 divided by 31). A stored component of 0 therefore becomes 0, and a stored component of 31 becomes 255. Intermediate values are distributed deterministically across the available output range.

This is a numerical expansion, not restoration of color information that was absent from the packed source: RGB555 has only 32 levels per channel, so several possible eight-bit values can never be produced. The rounding rule is stated explicitly because converters sometimes use a left shift, which maps the maximum component to 248, or bit replication, which describes the same intent through bit operations.

Validate packed colors in practical workflows

Use the unpacker when examining retro graphics, embedded display data, texture assets, binary records, emulator state, or any interchange format that identifies its colors as RGB555 with red in the most significant five-bit field. The distinction matters because related layouts such as BGR555 reverse channel positions, while RGB565 assigns six bits to green; those formats require different decoding and should not be silently guessed. Malformed text, signs, fractions, missing 0x prefixes on hexadecimal digits, trailing characters, and values outside the 15-bit unsigned range are rejected instead of being partially parsed.

That strictness prevents a value such as 123abc from quietly becoming 123. Because the algorithm uses no network, random source, clock, locale-sensitive parsing, or mutable state, identical valid input produces identical output in every supported execution channel.