Vedic meter
The verses of the Vedas have a variety of different meters. They are grouped by the number of padas in a verse, and by the number of syllables in a pada. Chandas (छन्दः), the study of Vedic meter, is one of the six Vedanga disciplines, or "organs of the vedas".
There are several Chandas. The seven main ones are:
Gayatri: 3 padas of 8 syllables containing 24 syllables in each stanza.
Ushnuk : 4 padas of 7 syllables containing 28 syllables in each stanza.
Anustubh: 4 padas of 8 syllables containing 32 syllables in each stanza. The typical shloka of classical Sanskrit poetry is in this category.
Brihati : 4 padas (8 + 8 + 12 + 8) containing 36 syllables in each stanza.
Pankti : 4 padas (sometimes 5 padas) containing 40 syllables in each stanza.
Tristubh: 4 padas of 11 syllables containing 44 syllabes in each stanza
Jagati: 4 padas of 12 syllables containing 48 syllables in each stanza
There are several others such as:
Virāj: 4 padas of 10 syllables
Kakubh
Principles
The main principle of Vedic meter is measurement by the number of syllables. The metrical unit of verse is the pāda ("foot", "quarter"), generally of eight, eleven, or twelve syllables; these are termed gayatri, tristubh and jagati respectively, after meters of the same name. A ṛc is a stanza of typically three or four padas, with a range of two to seven found in the corpus of Vedic poetry. Stanzas may mix padas of different lengths, and strophes of two or three stanzas (respectively, pragātha and tṛca) are common.