
Pat T. answered 04/26/20
Experienced Tutor Specializing in Tax Accounting
Hi Mo,
For any asset(s) you are claiming a deduction for, you would generally have the required information in your business records. For example, if you are using business or tax software, you will find that it has interview questions that prompt you through the appropriate answers and then records the information on a supporting worksheet.
If you are keeping records manually, you would need to compile and summarize the information. The schedule on page 20 of Pub 4562 (link below) has a good example of a depreciation worksheet - Instructions for Form 4562 https://www.irs.gov/pub/irs-pdf/i4562.pdf. You can keep a hand-written version, or you can duplicate the format in an Excel spreadsheet and keep it electronically.
You’ll find information on additional calculations, depending upon your asset classification, starting on page 28 in Pub 946 How to Depreciate Property - https://www.irs.gov/pub/irs-pdf/p946.pdf. There are examples of calculations starting on page 62. The quickest way to wade through the document is to do a key word search, for example do a Ctrl F, and type in “line 17”, to learn exactly how to calculate the number that goes on line 17.
Adequate records or evidence are required to support depreciation deductions, so whichever method you choose just make sure to include the required information shown in the worksheets, e.g., purchase date, date placed in service, description, cost, depreciable basis, etc., and to incorporate additional calculations for your asset classification type.