Hangul Syllables — Korean Characters in Unicode

Hangul Syllables in Unicode

Korean Hangul is unique among writing systems because its syllable blocks are algorithmically composed from individual letter components called Jamo. Unicode dedicates a massive block of 11,172 pre-composed syllables (U+AC00 to U+D7AF) covering every possible combination.

Hangul Composition Formula

Each syllable block consists of:

• Leading consonant (L): 19 possible values (U+1100–U+1112)
• Vowel (V): 21 possible values (U+1161–U+1175)
• Trailing consonant (T): 28 possible values (including none)

The code point is calculated as:

CP = 0xAC00 + (L × 21 + V) × 28 + T

For example, 한 (han) = 0xAC00 + (18 × 21 + 0) × 28 + 4 = U+D55C

UTF-8 Encoding

All pre-composed Hangul syllables use 3 bytes in UTF-8:

• 가 (ga) = U+AC00 → UTF-8: EA B0 80
• 한 (han) = U+D55C → UTF-8: ED 95 9C
• 글 (geul) = U+AE00 → UTF-8: EA B8 80

Jamo vs. Pre-composed

Unicode supports both individual Jamo characters (Hangul Jamo block U+1100–U+11FF) and pre-composed syllables. Most modern Korean text uses pre-composed forms for efficiency. The Hangul Compatibility Jamo block (U+3130–U+318F) provides standalone forms used in dictionaries and educational materials.

Normalization Considerations

Unicode normalization forms NFC and NFD produce different representations for Hangul:

• NFC: Uses pre-composed syllable (1 code point, 3 UTF-8 bytes)
• NFD: Decomposes into 2–3 Jamo (2–3 code points, 6–9 UTF-8 bytes)

The Unicode Inspector shows the actual code points in your text, helping you determine which normalization form is being used.