Garudapurana 2.13.11

2.13.11

śrīkṛṣṇa uvāca /
ṣaṇmāsairbrāhmaṇaḥ śudhyedyugme sārdhe tu bāhujaḥ /
sārdhamāsena vaiśyastu śūdro māsena śudhyati //

Śrī Kṛṣṇa said:
A brāhmaṇa becomes purified in six months, an arm-born [kṣatriya] in two and a half,
a vaiśya in a month and a half, and a śūdra is purified in a month.