Using the Applicable Convention in a Short Tax Year: Business Depreciation (2025 IRS Guide)

This guide covers “Using the Applicable Convention in a Short Tax Year” within business depreciation. The following material presents the IRS treatment of this topic, including the qualifications, exceptions, and examples in the source section. Read the rules alongside the facts of your own situation before deciding what to report, deduct, or document.

Adapted from Publication 946 (2025), How To Depreciate Property, published by the Internal Revenue Service. This guide retains the source edition’s years, amounts, deadlines, and examples. It is guidance for that edition, not a statement that the same figures apply to every tax year.

Context for these rules

You cannot use the MACRS percentage tables to determine depreciation for a short tax year. A short tax year is any tax year with less than 12 full months. This section discusses the rules for determining the depreciation deduction for property you place in service or dispose of in a short tax year. It also discusses the rules for determining depreciation when you have a short tax year during the recovery period (other than the year the property is placed in service or disposed of).

For more information on figuring depreciation for a short tax year, see Revenue Procedure 89-15, 1989-1 C.B. 816.

Using the Applicable Convention in a Short Tax Year

The applicable convention establishes the date property is treated as placed in service and disposed of. Depreciation is allowable only for that part of the tax year the property is treated as in service. The recovery period begins on the placed in service date determined by applying the convention. The remaining recovery period at the beginning of the next tax year is the full recovery period less the part for which depreciation was allowable in the first tax year.

The following discussions explain how to use the applicable convention in a short tax year.

Mid-month convention.

Under the mid-month convention, you always treat your property as placed in service or disposed of on the midpoint of the month it is placed in service or disposed of. You apply this rule without regard to your tax year.

Half-year convention.

Under the half-year convention, you treat property as placed in service or disposed of on the midpoint of the tax year it is placed in service or disposed of.

First or last day of month.

For a short tax year beginning on the first day of a month or ending on the last day of a month, the tax year consists of the number of months in the tax year. If the short tax year includes part of a month, you generally include the full month in the number of months in the tax year. You determine the midpoint of the tax year by dividing the number of months in the tax year by 2. For the half-year convention, you treat property as placed in service or disposed of on either the first day or the midpoint of a month.

For example, a short tax year that begins on June 20 and ends on December 31 consists of 7 months. You use only full months for this determination, so you treat the tax year as beginning on June 1 instead of June 20. The midpoint of the tax year is the middle of September (3½ months from the beginning of the tax year). You treat property as placed in service or disposed of on this midpoint.

Example.

Tara Corporation, a calendar year taxpayer, was incorporated on March 15. For purposes of the half-year convention, it has a short tax year of 10 months, ending on December 31, 2025. During the short tax year, Tara placed property in service for which it uses the half-year convention. Tara treats this property as placed in service on the first day of the sixth month of the short tax year, or August 1, 2025.

Not on first or last day of month.

For a short tax year not beginning on the first day of a month and not ending on the last day of a month, the tax year consists of the number of days in the tax year. You determine the midpoint of the tax year by dividing the number of days in the tax year by 2. For the half-year convention, you treat property as placed in service or disposed of on either the first day or the midpoint of a month. If the result of dividing the number of days in the tax year by 2 is not the first day or the midpoint of a month, you treat the property as placed in service or disposed of on the nearest preceding first day or midpoint of a month.

Mid-quarter convention.

To determine if you must use the mid-quarter convention, compare the basis of property you place in service in the last 3 months of your tax year to that of property you place in service during the full tax year. The length of your tax year does not matter. If you have a short tax year of 3 months or less, use the mid-quarter convention for all applicable property you place in service during that tax year.

You treat property under the mid-quarter convention as placed in service or disposed of on the midpoint of the quarter of the tax year in which it is placed in service or disposed of. Divide a short tax year into 4 quarters and determine the midpoint of each quarter.

For a short tax year of 4 or 8 full calendar months, determine quarters on the basis of whole months. The midpoint of each quarter is either the first day or the midpoint of a month. Treat property as placed in service or disposed of on this midpoint.

To determine the midpoint of a quarter for a short tax year of other than 4 or 8 full calendar months, complete the following steps.

1. Determine the number of days in your short tax year.

2. Determine the number of days in each quarter by dividing the number of days in your short tax year by 4.

3. Determine the midpoint of each quarter by dividing the number of days in each quarter by 2.

If the result of (3) gives you a midpoint of a quarter that is on a day other than the first day or midpoint of a month, treat the property as placed in service or disposed of on the nearest preceding first day or midpoint of that month.

Example.

Tara Corporation, a calendar year taxpayer, was incorporated and began business on March 15. It has a short tax year of 9½ months, ending on December 31. During December, it placed property in service for which it must use the mid-quarter convention. This is a short tax year of other than 4 or 8 full calendar months, so it must determine the midpoint of each quarter.

1. First, it determines that its short tax year beginning March 15 and ending December 31 consists of 292 days.

2. Next, it divides 292 by 4 to determine the length of each quarter, 73 days.

3. Finally, it divides 73 by 2 to determine the midpoint of each quarter, the 37th day.

The following table shows the quarters of Tara Corporation’s short tax year, the midpoint of each quarter, and the date in each quarter that Tara must treat its property as placed in service.

The last quarter of the short tax year begins on October 20, which is 73 days from December 31, the end of the tax year. The 37th day of the last quarter is November 25, which is the midpoint of the quarter. November 25 is not the first day or the midpoint of November, so Tara Corporation must treat the property as placed in service in the middle of November (the nearest preceding first day or midpoint of that month).

Using the guidance

Keep the documents that establish the dates, amounts, and circumstances described above. References to other chapters, forms, worksheets, or earlier and later sections refer to the linked IRS publication. Check the full publication and its updates before relying on a rule for a different tax year or a situation not addressed here.

Sources and further reading

• Publication 946 (2025), How To Depreciate Property: Figuring Depreciation Under MACRS — How Is the Depreciation Deduction Figured? — Figuring the Deduction for a Short Tax Year — Using the Applicable Convention in a Short Tax Year — Internal Revenue Service; 2025 edition.

The cited U.S. government text is in the public domain. Source accessed October 28, 2026. Fynoptic has organized this material for educational use and is independent of, and not endorsed by, the IRS.