Accounting
Core Accounting Principles
The handful of ideas that show up inside both GAAP and IFRS, despite their differences — matching, historical cost vs. fair value, revenue recognition, and consistency — the shared foundation both systems build on top of.
Definition
Core accounting principles are the ideas that show up inside both GAAP and IFRS, despite their specific technical differences — the shared foundation both standards are built on top of, rather than standard-specific technical rules.
Why this exists
GAAP and IFRS differ on plenty of specific technical rules, but neither was built from scratch independently — both rest on the same handful of foundational ideas about how to measure and report economic activity honestly and consistently. Understanding these shared principles is more durable and more useful than memorizing either standard's specific rules, since the principles themselves rarely change even as specific rules get revised over time.
Formula & mechanics
The Matching Principle
Expenses are recorded in the same period as the revenue they helped generate, not just whenever cash happens to move — the same underlying idea as Accrual vs. Cash Accounting, which is the mechanism that makes matching possible. Maria's bakery pays for a full year of flour upfront in January, but bakes and sells bread using that flour throughout the year. The matching principle requires spreading the flour's cost across the months she actually uses it, matched against the revenue those sales generate — not expensing the whole cost in January just because that's when the cash left her account.
Historical Cost vs. Fair Value
An asset can be recorded at what was originally paid for it (historical cost) or at what it's worth today (fair value). This genuinely matters for interpreting a balance sheet: Maria's bakery building, bought decades ago for $50,000, may still be listed at close to that original cost (minus depreciation) even though it might be worth $300,000 at today's market prices — the balance sheet isn't necessarily telling you what something is worth right now, just what was paid for it. Different situations call for different treatment: actively traded investments are often recorded at fair value because a reliable current market price actually exists, while a specialized building with no active market is recorded at historical cost because a "current value" would just be a guess.
The Revenue Recognition Principle
Revenue counts when it's actually earned — goods or services delivered — not necessarily when cash is received, tying directly to Accrual vs. Cash Accounting and to the adjusting-entries step of the accounting cycle. A catering client pays Maria a deposit in November for a wedding cake to be delivered in December. That deposit is not November revenue — it only becomes revenue in December, when the cake is actually delivered and the service is complete, even though the cash arrived a month earlier.
The Consistency Principle
A company must use the same accounting methods period over period — the same depreciation method, the same inventory valuation method — rather than switching whenever it would make a given period's numbers look better. If a company does change methods, it must disclose that change, tying to Footnotes & Disclosures. Maria has used straight-line depreciation for her ovens for five years; switching to declining-balance this year purely because it would flatter this year's profit would violate consistency, unless she has a genuine business reason and discloses the change clearly so readers understand why this year's numbers aren't directly comparable to prior years'.
Worked example
Putting all four principles together in one snapshot of Maria's bakery this month: her income statement shows revenue from a wedding cake delivered this month (recognized when delivered, per revenue recognition, not back when the deposit was paid), matched against the cost of the flour and ingredients actually used to make it (per the matching principle, not whenever she originally bought those supplies). Meanwhile, her bakery building stays listed on the balance sheet at its original historical cost minus accumulated depreciation, and a footnote confirms she used the same straight-line depreciation method she's used every prior year (per the consistency principle).
Four different principles, one coherent, comparable financial picture — and every one of them holds regardless of whether Maria's bakery happens to report under GAAP or IFRS.
Common misconceptions
“Matching means expenses and revenue must be recorded in the same period the cash actually moves.”
That's the opposite of what matching means. Matching pairs expenses with the revenue they helped generate, regardless of when cash actually changed hands — that's the entire point of accrual accounting.
“A company's balance sheet tells you what its assets are worth right now.”
Many assets are recorded at historical cost, not current market value — a balance sheet often understates or overstates what assets would actually sell for today, especially for long-held assets like real estate.
“A business can switch accounting methods freely, as long as the new method is technically allowed.”
The consistency principle requires using the same method period over period, and any genuine change has to be disclosed. Switching opportunistically to flatter a given period's results, without disclosure, undermines the comparability these principles exist to protect.
Also in the Glossary: Consistency Principle, Core Accounting Principles, Fair Value, Historical Cost, Matching Principle, Revenue Recognition Principle