What it means
GAAP stands for generally accepted accounting principles. It's the shared rulebook for turning a company's transactions into financial statements, so one company's balance sheet can be read the same way as another's.
In the US the rules are written by the Financial Accounting Standards Board (FASB), a private standard-setter. They're collected in one reference called the Accounting Standards Codification, usually shortened to ASC.
The Codification is organized by topic number. ASC 606 covers revenue, ASC 842 covers leases, ASC 360 covers equipment. Each topic says when something is recorded, at what amount, and where it shows up in the statements.
Much of it is judgment inside a framework. GAAP says equipment is depreciated over its useful life; your written policy says that means three years for servers. Once the policy exists, the same transaction gets booked the same way every month.
Plenty of what a finance team does sits outside GAAP altogether. Account numbering, board deck layout and metrics like ARR or burn are conventions, and nobody's GAAP books are wrong for doing them differently.
Say a startup bills and collects $12,000 from a customer in January for a year of software, and the same week pays $12,000 for a year of insurance. Cash-basis books show $12,000 of revenue and $12,000 of expense in January, then nothing for eleven months.
GAAP books show $1,000 of revenue and $1,000 of insurance expense in each month of the year. The unearned and unused parts wait on the balance sheet as deferred revenue and a prepaid. The bank balance is identical either way. What changes is whether January looks like a real month of the business.
GAAP books are kept on an accrual basis. A CPA review checks the bookkeeping against GAAP, and an audit ends in a formal opinion on whether the statements follow it. The tax return follows the tax code instead, so the Form 1120 preparer starts from your GAAP numbers and adjusts.
Why it matters. Investors, lenders, auditors and acquirers read your books against it. Books kept some other way get rebuilt during diligence, on the buyer's timeline.
The entry, worked
Acme's cash-basis books show $12,000 of revenue for a year of software billed and collected in January, and $12,000 of expense for a year of insurance paid the same week. Acme converts January to GAAP.
| Account | Debit | Credit |
|---|---|---|
| Revenue | $11,000.00 | |
| Deferred revenue | $11,000.00 | |
| Prepaid insurance | $11,000.00 | |
| Insurance expense | $11,000.00 | |
| Total | $22,000.00 | $22,000.00 |
January keeps $1,000 of revenue and $1,000 of insurance expense; the other eleven months of each wait on the balance sheet.
Common questions
Does a private startup have to follow US GAAP?
Not by statute, as long as it isn't filing with the SEC. The requirement usually arrives by contract: a loan agreement, an investor's information rights or an audit someone asks for will call for GAAP statements. That's why most venture-backed companies end up keeping GAAP books.
Is GAAP the same as tax accounting?
No. GAAP decides what goes in your financial statements, and the tax code decides what goes on your return. The two often differ, and the gaps are tracked as book-to-tax differences.
Are there simpler rules for private companies?
In a few places. The Private Company Council has added alternatives inside GAAP. One example: a private company can elect to amortize goodwill over up to ten years instead of testing it for impairment every year.
Where it comes up
The glossary entries, founder guides and lessons on this site that use the term and link here.
- US GAAP for early-stage startups, in plain EnglishAccrual accounting, revenue recognition (ASC 606), leases (ASC 842), stock compensation and capitalized software: what each means for a small company.Guide · 4 min
- Why startups should close their books every monthA monthly close turns a bank balance into numbers an investor, an auditor or a 409A firm will accept. What it is, and why it gets expensive to skip.Guide · 4 min
- Audit-ready books before your Series AInvestors, lenders and auditors ask for the same things: accrual statements, reconciled accounts and support for every balance. How to be ready first.Guide · 4 min
- Can you vibe code your startup’s accounting?AI coding tools build a finance dashboard in an afternoon, but not a closed, reconciled, GAAP-basis ledger. Where the line is, and how to stay inside it.Guide · 3 min
- Deferred revenue for SaaS startups, explainedAn annual prepayment is cash today and revenue over a year. How deferred revenue works under ASC 606, why it’s a liability, and the schedule behind it.Guide · 4 min
- How to account for SAFEs on your balance sheetA SAFE is cash today and shares later. Why it usually sits with liabilities, how the cap and discount set conversion, and what to book at the priced round.Guide · 4 min
- The R&D tax credit and Section 174A for startupsEngineering salaries can earn a federal R&D credit against payroll tax, and Section 174A lets you deduct US research again. What qualifies, what to track.Guide · 5 min
- Stock options, 409A valuations and vesting for startupsHow option strike prices are set by a 409A valuation, how vesting and the cliff work, and why ASC 718 makes every grant an expense on your P&L.Guide · 4 min
- Form 1120: what to give your tax preparer, and whenWhat a startup hands its tax preparer for Form 1120: closed books, a balance sheet that ties to Schedule L, book-to-tax items, ownership and 1099s.Guide · 5 min
- How to read an income statement (P&L)Revenue, cost of revenue, gross margin, operating expenses and net income, read line by line, on accrual basis, with the mistakes founders make most.Guide · 7 min
- Balance sheet explained for startupsAssets equal liabilities plus equity. What each startup line means, from deferred revenue to the SAFE and the accumulated deficit, and why it must balance.Guide · 7 min
- Cash flow statement explained: why profit isn’t cashHow the cash flow statement starts at net income, adds back non-cash costs and working capital, splits three activities and ties to the balance sheet.Guide · 5 min
- General ledger and double-entry bookkeeping, explainedHow double entry works: journal entries, debits and credits, normal balances, running balances, the trial balance, and why posted entries are reversed.Guide · 6 min
- Chart of accounts for startups: a starting templateA starting chart of accounts for a US startup: number ranges, the expense accounts you need, and when to add an account versus a class or tracking tag.Guide · 6 min
- MRR vs GAAP revenue under ASC 606MRR and ARR are operating metrics; revenue under ASC 606 is earned over time. How annual prepayments and churn split them, and how to reconcile the two.Guide · 6 min
- Cash vs accrual accounting for startups, and the IRS ruleCash or accrual for a startup: why investors and auditors read accrual, when the IRS lets a C-corp file on cash, and the 2026 gross receipts limit.Guide · 5 min
- Accrued expenses vs accounts payable: the differenceAP is a bill you’ve received; an accrued expense is a cost incurred before the bill arrives. When to accrue, and how reversing entries work, by example.Guide · 5 min
- Bad debt and write-offs: allowance vs direct methodHow to book a customer who won’t pay: the GAAP allowance under ASC 326, the direct write-off the IRS requires, and what to do if the money comes back.Guide · 7 min
- SaaS revenue recognition under ASC 606, step by stepASC 606’s five steps applied to a startup SaaS contract: annual prepay, implementation fees, usage and multi-year deals, with the entries.Guide · 6 min
- Why the books existBookkeeping is not record-keeping for its own sake. It is a system built so that an error announces itself and every figure traces back to an event.Lesson 1
Read further
General information for US companies, not tax, legal or accounting advice. Check the specifics with a CPA before you act on them.