GAAP vs. IFRS: Key Differences Explained

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GAAP and IFRS are not the same, though they cover the same ground. U.S. generally accepted accounting principles (GAAP) is the framework U.S. companies use to prepare financial statements. International Financial Reporting Standards (IFRS) is the framework most other major economies use. The biggest difference is approach: GAAP is rules-based, with detailed guidance for specific transactions and industries, while IFRS is principles-based, giving broader guidance that relies more on judgment. That difference produces concrete gaps in how inventory, development costs, asset values, leases and some cash flows are reported. The same company can therefore show different profit and balance sheet figures depending on which framework it follows.

Who sets each standard and where it applies

The FASB, a private standard setter recognized by the SEC, writes and updates U.S. GAAP. Companies whose stock trades publicly in the U.S. must prepare their statements under GAAP and also follow SEC reporting rules.

The IASB, founded in 2001 and based in London, issues IFRS. Its purpose is a common accounting language, so a company’s results can be compared across borders. As of May 2025, 161 jurisdictions had publicly committed to IFRS, and 148 required it for publicly listed companies. IFRS is standard in the EU and widely used across Asia and South America.

The SEC has discussed moving U.S. reporting to IFRS for years but has not adopted it, and a switch is not expected in the near term. One practical bridge already exists: since 2007, foreign companies listed in the U.S. may file statements prepared under IFRS as issued by the IASB without reconciling them to GAAP.

Rules-based vs. principles-based accounting

The difference in approach explains most of the specific gaps.

GAAP answers many questions with explicit criteria, thresholds and industry-specific guidance. That makes outcomes more predictable and easier to audit against a checklist, but it can encourage transactions structured to land just on one side of a rule.

IFRS states a principle and expects preparers to apply it to the economics of a transaction. Its guidance is much shorter overall, which leaves more room for interpretation and often requires longer disclosures explaining the judgments made. The tradeoff is less consistency between companies that interpret the same principle differently.

The main differences in practice

Inventory

This is the most cited difference. GAAP permits last-in, first-out (LIFO), which assumes the newest inventory is sold first. IFRS bans LIFO. Both frameworks permit first-in, first-out (FIFO) and weighted average cost.

The frameworks also differ on write-downs. When inventory loses value, both require it to be written down. IFRS allows that write-down to be reversed if the value later recovers, up to the original cost. GAAP does not allow the reversal.

Research and development

Under GAAP, R&D costs are generally expensed as incurred, with limited exceptions such as certain software costs. IFRS also expenses research costs, but once a project reaches the development phase and meets set criteria (technical feasibility, intent and ability to complete it, likely future economic benefit), the development costs must be capitalized as an intangible asset. Internal costs such as building prototypes can fall into this category. A company with heavy development spending can therefore report higher assets and, in the early years, higher profit under IFRS.

Property, plant and equipment

GAAP requires long-lived assets to be carried at historical cost less depreciation and impairment. IFRS allows a revaluation model, under which a company can carry a class of assets at fair value and update it regularly. Two companies owning identical buildings can show very different asset totals if one uses revaluation under IFRS.

Investments

Both frameworks require investments such as shares, bonds and derivatives to be sorted into categories, and both track changes in their value. The criteria differ. GAAP’s categories depend heavily on the legal form of the instrument, such as whether it is a debt security or a loan. IFRS 9 classifies financial assets by the company’s business model for holding them and the nature of their contractual cash flows, regardless of legal form. The category determines whether value changes flow through profit or loss.

Leases

Both frameworks now put most leases on the lessee’s balance sheet. IFRS 16 uses a single model that treats leases much like financed purchases, so the income statement shows depreciation and interest. GAAP keeps a split between finance leases and operating leases, and operating leases produce a single straight-line lease expense. Operating profit and EBITDA can look different under each framework even when cash payments are identical.

Cash flow statement

Under GAAP, interest paid and interest and dividends received are classified as operating cash flows, and dividends paid as financing. IAS 7 has given IFRS reporters a choice of classification for these items, so an IFRS company may show interest paid under financing and report higher operating cash flow than a GAAP peer. IFRS 18, which takes effect for periods beginning in 2027, narrows that choice for most companies. Anyone comparing operating cash flow across the frameworks should check where interest sits.

Example: how LIFO changes reported profit

A hypothetical retailer buys 100 units at $10, then 100 more at $12 as prices rise, and sells 100 units for $20 each.

• LIFO (allowed under GAAP): cost of goods sold uses the newest units at $12, so gross profit is $2,000 minus $1,200, or $800. Ending inventory is valued at $1,000.
• FIFO (allowed under both): cost of goods sold uses the oldest units at $10, so gross profit is $2,000 minus $1,000, or $1,000. Ending inventory is valued at $1,200.

Same purchases, same sale, same cash. In a period of rising costs, LIFO reports lower profit and lower taxable income, which is a reason some U.S. companies use it. A company switching from GAAP to IFRS would have to drop LIFO and restate inventory, which would raise reported profit and its tax base in the U.S. That cost is one of the practical obstacles to U.S. adoption of IFRS.

Similarities between GAAP and IFRS

Both frameworks use accrual accounting, both produce a balance sheet, income statement, cash flow statement and statement of changes in equity, and both rest on concepts such as relevance and faithful representation. Starting with the 2002 Norwalk Agreement, the FASB and IASB worked on convergence projects. The most visible result is revenue recognition: ASC 606 and IFRS 15 use the same five-step model, so revenue is now recognized largely the same way under both. Leases were a joint project too, though the final standards differ in the ways described above.

Which is better?

It depends on the user. A principles-based system can capture the substance of a transaction more accurately and suits a global investor base. A rules-based system offers predictability and comparability among U.S. companies. Because most of the world reports under IFRS, international companies and investors gain from a single standard, while U.S. companies would face real costs from switching.

For analysts, the practical point is that ratios built on GAAP and IFRS statements are not directly comparable until differences in inventory, development costs, leases and cash flow classification are adjusted.

FAQs

The Bottom Line

GAAP and IFRS differences matter most to analysts and investors comparing U.S. companies with peers abroad. Inventory methods, development costs, lease accounting and cash flow classification can shift reported profit, assets and operating cash flow even when the underlying cash is the same. Ratios from statements prepared under different frameworks should be adjusted for these items before comparison, starting with where interest sits in the cash flow statement.