2,870. Nezirus for More Than 30 Days

Hilchos Nezirus 3:3

If someone explicitly named a duration longer than 30 days – 31 days, 40 days, 100 days, 100 years, etc. – then he’s a nazir for the period he named, no more and no less.

Hilchos Nezirus 3:4

If someone says that he’ll be a nazir for one hour, he must observe a nazirite period of 30 days. If he said that he’ll be a nazir for 30 days and one hour, then he must observe nezirus for 31 days. This is because nezirus is counted in days, not hours.