调值（tone number）是声调的实际读音，指声音高低、升降、曲直、长短的形式。调值只表示相对音高，而不表示绝对音高。

表示调值时，经常会使用五度标记法。

Tone numbers are numerical digits used like letters to mark the tones of a language. The number is usually placed after a romanized syllable. Tone numbers are defined for a particular language, so they have little meaning between languages.

Other means of indicating tone in romanization include diacritics, tone letters, and orthographic changes to the consonants or vowels. For instance, in Mandarin, the syllable 马 (which has a falling-rising tone) is represented in Wade-Giles romanization as ma, with a tone number; in Hanyu Pinyin as mǎ, with a diacritic; and in Gwoyeu Romatzyh as maa, with a change in the vowel.