Tax vs Book Depreciation: 3 Key Differences and Example

Book depreciation is the expense a company records in its financial statements under GAAP, spreading cost minus salvage value over the asset’s expected useful life. Tax depreciation is the deduction on the tax return, usually under MACRS, the IRS system with set recovery periods, mostly faster methods, and no salvage value. The gap is mostly about timing.

GAAP means U.S. generally accepted accounting principles, and MACRS means the Modified Accelerated Cost Recovery System. Because the two systems follow different rules, an asset can have zero tax basis but still show a positive book value, and one sale can produce a book loss and a taxable gain at the same time. Below, you’ll see the three key differences, a full six-year example, and how the gap creates deferred taxes.

Key takeaways

• Book depreciation follows GAAP (FASB ASC 360) and spreads cost minus salvage value over the asset’s expected useful life.
• Tax depreciation follows Internal Revenue Code section 168 (MACRS), with prescribed recovery periods, conventions, and zero salvage value.
• MACRS often front-loads deductions, so taxable income is lower in early years and higher later.
• The gap between book value and tax basis is a temporary difference, which creates deferred taxes under ASC 740.
• In a simple case like the example below, both systems recover the same net cost over the asset’s life once you include the gain or loss on sale.

What are the three key differences between tax and book depreciation?

Book depreciation under U.S. generally accepted accounting principles (GAAP) allocates depreciable cost over the period the asset is expected to provide service. Tax depreciation follows tax rules. The Modified Accelerated Cost Recovery System (MACRS) generally applies to property placed in service after 1986 and uses prescribed recovery periods.

These are differences in the rules, not a claim that book and tax amounts must always differ. If the relevant estimates and permitted treatments align, amounts can coincide. Also, GAAP does not require straight-line depreciation for every asset, and MACRS does not always require an accelerated method.

For example, MACRS straight-line depreciation can still differ from book straight line because the lives, residual amounts, and timing conventions differ.

How do tax and book depreciation schedules compare? A worked example

Hypothetical example. Birch Design buys and places computers in service on January 1 for $30,000. For financial reporting, it expects six years of service and a $6,000 salvage value, and uses straight line. For tax, assume five-year GDS property, 200% declining balance, and the half-year convention.

Assume full tax years, 100% business use, no section 179 deduction, no bonus depreciation, and no other basis adjustments. The computers remain in service through the full recovery schedule. GDS means General Depreciation System.

Annual book depreciation = ($30,000 − $6,000) ÷ 6 = $4,000. Tax depreciation uses the five-year MACRS table percentages against $30,000, without subtracting the $6,000 salvage estimate.

At the end of year one, book value is $26,000 and adjusted tax basis is $24,000. At the end of year six, book value is $6,000 and adjusted tax basis is zero. Neither amount is automatically the computers’ market value.

The calculation of the tax column is explained in MACRS depreciation and IRS table percentages. Notice that the largest tax deduction occurs in year two: the first year is limited by the half-year convention.

Want more practice with schedules like this? The Intermediate Accounting course walks through depreciation, disposals, and deferred taxes step by step, and you can try the free sample course first.

Why can one sale create a book loss and a taxable gain?

Immediately after year six, suppose Birch sells the computers for $4,500. Ignore selling costs and assume no further depreciation is available. Compare the same proceeds with each system’s remaining amount:

There is no contradiction. Tax already deducted the entire $30,000 cost; book depreciation stopped at the $6,000 salvage estimate. The sale recovers $4,500 against a zero tax basis, but fails to recover $1,500 of the book carrying amount. Quick tip for CPA REG and EA candidates: computers are section 1245 property, so the entire $4,500 tax gain is depreciation recapture taxed as ordinary income. For the book journal entry that records a sale like this, see retirement of fixed assets.

Now reconcile the lifetime pretax-income effect. Book reporting reduces income by $24,000 depreciation plus $1,500 loss, or $25,500. Tax reporting reduces taxable income by $30,000 depreciation less $4,500 gain, also $25,500. Both equal cost minus proceeds: $30,000 − $4,500.

This equality follows from the example’s assumptions. It does not mean each year’s income, tax payments, or present value is identical. Nor should you assume all differences between tax rules and GAAP reverse; this example concerns the recovery of one depreciable asset’s cost.

How do timing differences affect cash taxes and deferred taxes?

Accelerated deductions can reduce taxable income earlier and leave fewer deductions later. With an unchanged tax rate and the ability to use the deductions, that shifts tax payments to later periods. It does not create additional operating sales or reduce the original cash paid for equipment.

The remaining book and tax amounts create a temporary difference that reverses as the asset is recovered or sold. Under ASC 740, Income Taxes, that gap is the starting point for deferred tax accounting.

Here is a quick look using Birch’s numbers. Assume Birch is a taxable corporation and the enacted 21% tax rate is expected to apply when the temporary difference reverses. At the end of year one, book value ($26,000) is higher than tax basis ($24,000) by $2,000. That is a taxable temporary difference, so Birch would report a deferred tax liability of $420 ($2,000 × 21%). By the end of year six, the difference is $6,000 ($6,000 book value minus zero tax basis), so the liability is $1,260. When Birch sells the computers, the $1,500 book loss and $4,500 tax gain together close the $6,000 gap, and the liability reverses to zero.

Full measurement rules, such as valuation allowances and tax rate changes, go beyond this guide.

Current-law note, checked November 10, 2026: older textbook schedules that phase bonus depreciation down by 20 percentage points a year now apply only to property acquired on or before January 19, 2025. The IRS summary of the 2025 law explains the permanent 100% additional first-year deduction, often called bonus depreciation, for qualifying property acquired and placed in service after January 19, 2025. You may see the law called the One Big Beautiful Bill Act or, on newer IRS pages, the Working Families Tax Cuts. Other eligibility conditions still matter. Our examples exclude bonus depreciation to isolate ordinary MACRS mechanics.

To see how much bonus depreciation can widen the gap, suppose Birch had qualified for and claimed 100% bonus depreciation instead. Its year-one tax deduction would be the full $30,000, while book depreciation stays at $4,000, so the year-one gap jumps from $2,000 to $26,000. Section 179 expensing can have a similar effect, subject to its own dollar and taxable income limits.

Common tax vs book depreciation mistakes

Do not copy a tax return’s deduction into the financial statements simply to avoid a second schedule. The book method still needs to reflect a systematic, rational allocation over expected service. Conversely, do not substitute the book useful life or salvage value into a MACRS calculation. One exception worth knowing: many small private companies prepare statements on the income tax basis of accounting, a special purpose framework, where using tax depreciation is the whole point. That is a different framework, not GAAP. See special purpose frameworks (OCBOA) for how that works.

Another common error is stopping the comparison at accumulated depreciation. Include disposal proceeds and the related gain or loss when reconciling the lifetime effect. A tax gain can coexist with a book loss because the starting bases differ.

The half-year convention applies when neither the mid-month convention nor the mid-quarter convention applies. The mid-quarter convention generally applies when more than 40% of the total depreciable basis of eligible MACRS property placed in service during the tax year relates to property placed in service during the last three months of that year. Exclude nonresidential real property, residential rental property, railroad grading or tunnel bores, and property placed in service and disposed of in the same year. For the 40% test, reduce basis for section 179 deductions and personal use, and calculate the test before any reduction for bonus depreciation. When the mid-quarter convention applies, use the applicable quarterly percentages.

Practice questions with explained answers

1. Equipment costs $42,000, has a $6,000 book salvage value, and a six-year book life. What is annual straight-line book depreciation?

Answer: $6,000: ($42,000 − $6,000) ÷ 6. The salvage estimate reduces the book depreciable amount.

2. Assume that equipment is five-year MACRS property with a 20% first-year table rate. What is the tax deduction?

Answer: $8,400: $42,000 × 20%, assuming no other adjustments. The $6,000 salvage estimate is ignored for MACRS.

3. An asset with a $7,000 book value and zero tax basis sells for $5,000. What are the results?

Answer: A $2,000 book loss and a $5,000 taxable gain. Subtract the appropriate remaining amount from the same proceeds.

Frequently asked questions

Is tax depreciation always larger than book depreciation?

No. It can be larger early and smaller later. The example’s tax deductions fall below book depreciation in years four through six.

Can tax and book both use straight line?

Yes. But different recovery periods, salvage values, or timing conventions can still produce different annual amounts.

Does zero tax basis mean zero selling price?

No. Basis is an accounting amount used for tax calculations, not a market-price estimate.

Is it legal to use different depreciation for books and taxes?

Yes. GAAP and the tax code have different goals, so most businesses keep separate book and tax depreciation records. This is normal and expected, as long as each set follows its own rules.

Where does the book-tax depreciation difference show up on a corporate tax return?

On Form 1120, Schedule M-1 reconciles net income per books to taxable income, and depreciation differences are one of its standard adjustments. Corporations with total assets of $10 million or more generally must file Schedule M-3. Corporations required to file Schedule M-3 that have less than $50 million in total assets may complete Part I of Schedule M-3 and Schedule M-1 instead of Parts II and III.

Does tax vs book depreciation create a deferred tax liability?

Usually, yes. When tax depreciation runs ahead of book depreciation, book value is higher than tax basis. That taxable temporary difference creates a deferred tax liability under ASC 740. In the Birch example, the year-one difference of $2,000 at an assumed 21% rate is a $420 liability.

Sources and lesson context

This original study guide follows Wiley Intermediate Accounting, Appendix 10A. The tax mechanics and table percentages are supported by IRS Publication 946. All examples and questions are hypothetical; the current-law note is separate from the classroom assumptions. The book rules come from FASB ASC 360, Property, Plant, and Equipment, and ASC 740, Income Taxes. The tax rules come from Internal Revenue Code section 168.

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