closing
30-day month method
The 30-day month method, sometimes called the statutory or banker's year, is a proration method that treats every month as having 30 days and the year as 360 days. It simplifies calculations of daily amounts for taxes, rent, interest, and other prorated items. The alternative is the 365-day method, which uses the actual number of days in each month. Which method is customary varies by area and contract.
- Exam tip
- Read the question for the method. With the 30-day method, divide an annual amount by 360 and a monthly amount by 30, even for February or 31-day months.
- Example
- Annual taxes of $3,600 divided by 360 equal $10 per day; for a closing on March 15, the seller owes 75 days, or $750.
Related terms & state variants
Sources
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Last verified: 2026-10-23