Computer Software Depreciation: IRS Rules, Section 179, and Bonus Rules

Computer software depreciation lets a business recover the cost of purchased software over time rather than deducting it all at once, and federal tax law sets the default recovery period at 36 months using straight-line depreciation. In practice, most businesses skip that default. Section 179 expensing and 100% bonus depreciation usually let you write off the entire cost of qualifying software in the year you place it in service. Which route fits depends on how you acquired the software, whether it was customized, and how much taxable income you have to absorb the deduction.

Which Software You Can Depreciate

The IRS treats software differently based on how you got it. Off-the-shelf software qualifies for the standard depreciation rules if it clears three tests: it is readily available for purchase by the general public, it is sold under a nonexclusive license, and it has not been substantially modified.¹ Most commercial applications sold through normal retail or online channels meet all three.

The software also has to be used in your trade, business, or income-producing activity.¹ If you use it for both business and personal purposes, only the business-use share is deductible, and you have to document a reasonable allocation.

Bundling changes things. When software comes packaged with hardware and the invoice does not state the software price separately, the cost gets absorbed into the hardware’s basis and follows the hardware’s recovery schedule. If the invoice breaks the software out as its own line item, it follows the software rules.

Upgrades and Maintenance

An upgrade that adds genuinely new functionality is a capital expenditure and gets depreciated separately from the original software. A patch, bug fix, routine update, or annual maintenance and support contract is an ordinary business expense in the year you pay for it. Getting this wrong in either direction distorts your deductions.

The 36-Month Default Method

Under Section 167(f)(1), the default recovery period for qualifying purchased software is 36 months, straight-line.² Divide the total cost by 36 and deduct an equal amount each month.

The clock starts the month you place the software in service, meaning it is installed and ready for its intended business use.¹ Buying is not enough. If you purchase in October but don’t install until January, depreciation begins in January.

Your cost basis is the purchase price plus sales tax, freight, and installation fees.¹ Ongoing subscription fees and maintenance costs are not part of the basis; deduct those separately as ordinary expenses.

Deducting the Full Cost in Year One

Two accelerated options let most businesses skip the 36-month schedule and write off the whole cost immediately.

Section 179 Expensing

Section 179 lets you deduct the full purchase price of off-the-shelf software in the year you place it in service, as long as the software passes the same three tests (publicly available, nonexclusive license, not substantially modified).¹ For tax years beginning in 2026, the maximum Section 179 deduction is $2,560,000, and the deduction phases out dollar-for-dollar once total qualifying purchases for the year exceed $4,090,000.

Section 179 cannot exceed your taxable business income for the year. If your business earns $200,000 and you buy $300,000 of qualifying property, you can deduct $200,000 under Section 179 and carry the remaining $100,000 forward.

100% Bonus Depreciation

The One Big Beautiful Bill Act permanently restored 100% bonus depreciation under Section 168(k) for qualified property acquired after January 19, 2025.³ For most software purchased in 2026, this alone wipes out the full cost in year one.

The acquisition date matters. Software acquired before January 20, 2025, but not placed in service until 2026 qualifies for only 20% bonus depreciation under the original phase-down schedule.⁴ That mainly affects software contracted for earlier but deployed later. Anything purchased fresh in 2026 gets the full 100%.

Unlike Section 179, bonus depreciation has no dollar cap and no taxable income limitation. It can create a net operating loss. That is useful when you have enough income to absorb the deduction, or when a loss carryforward fits your longer-term plan; it is not automatically the right choice just because it is available.

Software Your Business Develops In-House

Software developed internally follows separate rules. Under the newly enacted Section 174A, domestic research and experimental expenditures paid or incurred in tax years beginning after December 31, 2024, can be fully expensed in the year they occur. Software development costs are classified as research and experimental expenditures, so in-house development costs for 2026 are immediately deductible.

This reversed a Tax Cuts and Jobs Act rule that had required capitalizing and amortizing domestic software development costs over five years from 2022 through 2024. Businesses that capitalized during those years can elect to accelerate the remaining unamortized balance into 2025 or spread it across 2025 and 2026.

One boundary: software development conducted outside the United States must still be capitalized and amortized over 15 years. There is no immediate-expensing option for foreign research expenditures.

Software Acquired With a Business

Software that comes along when you buy an entire business or a substantial part of one is generally a Section 197 intangible. You amortize it ratably over 15 years starting the month you acquire it, regardless of how quickly the software becomes obsolete.⁵ Section 179 and bonus depreciation cannot accelerate this timeline.

There is a carve-out. Off-the-shelf software that meets the standard three tests is specifically excluded from Section 197, even when acquired as part of a business purchase.⁵ That software follows the normal depreciation rules. So if you buy a company whose assets include a proprietary customer platform and a stack of Microsoft Office licenses, the custom platform goes on the 15-year schedule while the Office licenses follow the standard rules.

SaaS and Subscription Software

Cloud-based software subscriptions are not depreciable at all. Paying a monthly or annual fee for Software-as-a-Service is paying for access, not acquiring property, so those fees are deductible as ordinary business expenses in the year you pay them. No cost basis, no placed-in-service date, no depreciation schedule.

Implementation costs are where this gets messy. If a SaaS vendor charges separately for customization, configuration, or integration during setup, some of those costs may need to be capitalized rather than expensed immediately. Costs during the application development stage of a cloud computing arrangement are capitalized; costs during the preliminary project stage, training, data conversion, and ongoing operation are expensed as incurred.

In practical terms, if you pay $500 a month for a cloud accounting platform, that is a straight business expense. If you also pay a consultant $40,000 to build custom functionality on top of it, the customization work likely needs to be capitalized. Keep implementation invoices separate from ongoing subscription invoices so the two do not blur together at tax time.

When Software Becomes Obsolete Before It Is Fully Depreciated

Software sometimes becomes worthless before its 36-month period ends. If you permanently stop using it and have no intention of transferring it to anyone else, you can claim an abandonment loss for the remaining undepreciated cost, generally as an ordinary loss in the year you abandon it.⁶

“Permanently” is the operative word. Shelving software because a project stalled does not count. You need to genuinely give up all rights and use. Document the abandonment with a memo explaining why the software is no longer useful, the date you stopped using it, and confirmation that no one in the organization retains access. The loss equals your adjusted basis at the time of abandonment: original cost minus depreciation already claimed.

Reporting Software Depreciation on Form 4562

All depreciation and amortization claims run through IRS Form 4562, attached to your annual income tax return.⁷ Where you report depends on the method:

Section 179 expensing goes in Part I. Enter the cost of qualifying software and the elected deduction amount.
Bonus depreciation goes in Part II (Special Depreciation Allowance), reporting the 100% first-year deduction for qualifying property.
The 36-month straight-line method also goes in Part II, on Line 16. The IRS instructions specifically direct taxpayers to report computer software depreciated over 36 months on this line, not in Part VI.⁸
Section 197 amortization goes in Part VI, which covers intangible assets including software acquired with a business.

Keep purchase invoices, licensing agreements, installation records, and deployment dates for at least three years after filing the return that claims the final depreciation deduction. If you claim an abandonment loss, retain documentation showing when and why you stopped using the software. The burden of proof sits with you if the IRS asks.

1
Internal Revenue Service. Publication 946 (2025), How To Depreciate Property
2
Office of the Law Revision Counsel. 26 USC 167 – Depreciation
3
Internal Revenue Service. Treasury, IRS Issue Guidance on the Additional First Year Depreciation Deduction Amended as Part of the One Big Beautiful Bill
4
Internal Revenue Service. Rev. Proc. 2026-15
5
Office of the Law Revision Counsel. 26 USC 197 – Amortization of Goodwill and Certain Other Intangibles
6
Internal Revenue Service. Publication 544, Sales and Other Dispositions of Assets
7
Internal Revenue Service. About Form 4562, Depreciation and Amortization
8
Internal Revenue Service. Instructions for Form 4562 (2025)