To book an accrual, debit the relevant expense account and credit an accrued liability account for the estimated amount at period end, then post a reversing entry on the first day of the next period so the actual invoice, when it arrives, flows through accounts payable without being counted twice. That is the whole mechanic. The work sits in identifying which costs need one, sizing the estimate defensibly, and documenting the entry so an auditor or tax preparer can follow it later.
The reason accountants bother is the matching principle: financial statements should reflect what a business actually owed and earned during a period, not just what cleared the bank. If the electricity was consumed in March, the expense belongs in March, even if the bill shows up in April.
What Qualifies as an Accrual
An accrual captures any obligation incurred or revenue earned before period end that hasn’t yet been invoiced, billed, or paid. The common categories:
- Wages and payroll taxes for days worked before month-end but paid after
- Utilities — electric, gas, water — where the bill arrives weeks after the service period
- Interest that accumulates daily but bills quarterly or semi-annually
- Legal, consulting, or audit work performed before period end but not yet billed
- Sales tax collected from customers but not yet remitted
- Accrued revenue: work completed for a client before period end that hasn’t been invoiced
To find them, pull the general ledger at cutoff and compare it against recurring costs the business normally incurs. A missing line item is a clue. Cross-reference the accounts payable aging for obligations received but not yet entered, and check receiving logs or project completion reports to confirm the goods or services actually landed before the period closed. Most accounting teams also run a “look-back” during the first few business days of the new period: any late-arriving invoice that clearly belongs to the prior period gets flagged and accrued back. Skip that step and the same expenses will quietly go missing every month.
Estimating the Amount
Start with the most concrete number you can get. A purchase order, signed contract rate, or fixed-fee agreement gives you an exact or near-exact figure with no guesswork. For costs that fluctuate — utilities are the classic case — a twelve-month rolling average smooths seasonal spikes and gives auditors a defensible basis. If the vendor’s portal shows real-time usage, apply the current rate schedule to actual consumption.
Payroll Proration
When a pay period straddles two months, accrue the portion earned before month-end:
(Working days in the closing month after the last payday ÷ Total working days in the pay period) × Gross pay for that pay period
If a biweekly pay period has 10 working days and 3 fall after month-end close, accrue 3/10 of that cycle’s gross wages. Include the employer’s share of payroll taxes and benefits, which accrue alongside the wages.
Percentage of Completion
For multi-month contracts partially done at period end, accrue based on progress. A contractor 60% through a $50,000 project would accrue $30,000, less any amounts already billed. This suits construction, consulting engagements, and any service delivered over time.
Whatever method you use, document the logic. If the eventual invoice differs meaningfully from your estimate, you’ll want a clear calculation trail to explain why.
The Journal Entry
Two lines. Debit the appropriate income-statement expense account for the estimated amount. Credit a balance-sheet liability account for the same amount. Books balance, the income statement carries the cost in the correct period, and the balance sheet shows the obligation.
A $12,000 accrual for December consulting fees looks like this:
- Debit: Consulting Expense — $12,000
- Credit: Accrued Expenses — $12,000
Use the description field. “Accrual — Smith & Co. consulting, December 2025 work, invoice pending” saves everyone time during month-end review. Post before the sub-ledgers close, or the entry won’t appear in the reports.
Accrued Revenue
The same logic runs in reverse when you’ve earned revenue but haven’t billed. Finish a $5,000 project on December 31 that won’t be invoiced until mid-January, and December’s entry is:
- Debit: Accounts Receivable — $5,000
- Credit: Service Revenue — $5,000
When the invoice goes out and payment arrives, the receivable clears through normal billing. Under ASC 606, revenue is recognized when a performance obligation is satisfied — essentially, when the promised goods or services transfer to the customer. For most straightforward accruals the question reduces to whether the work was done before period end.
Reversing the Entry Next Period
Post a reversing entry on the first day of the new period. It flips the original: debit the accrued liability, credit the expense. That zeros out the estimate so the real invoice, when it clears accounts payable, posts cleanly.
Using the consulting example, the January 1 reversal is:
- Debit: Accrued Expenses — $12,000
- Credit: Consulting Expense — $12,000
When the actual $12,500 invoice arrives and is paid in January, the full $12,500 posts to Consulting Expense. Because the reversal already left a $12,000 credit in that account, the net January impact is only $500 — the estimation variance. That’s exactly how it should work. Skip the reversal and you’ll record the same economic event twice, suppressing net income in the current period and generating budget variances that send controllers hunting for a problem that isn’t there.
Most ERPs offer an auto-reversing entry type. Flag the original as auto-reversing (the label varies by platform) and the system generates a reversal dated the first day of the next period.1Oracle Help Center. Creating Auto-Reversing Journals The auto-reversal typically lands in “Approved” status but still needs to be posted, so build a check into your period-open procedures. A reversal sitting approved-but-unposted is functionally no reversal at all.
When It’s Worth Booking
Not every unpaid bill at cutoff warrants a manual entry. Most companies set a materiality threshold — a dollar floor below which accruals aren’t required. A $47 office-supply order that arrives on the last day of the quarter usually isn’t worth the effort.
There’s no universal number. The SEC has rejected a bright-line 5% rule and stressed that materiality involves both quantitative and qualitative analysis: a numerically small misstatement can still be material if it masks a change in earnings trends, hides a failure to meet analyst expectations, affects loan covenant compliance, or increases management compensation.2U.S. Securities and Exchange Commission. SEC Staff Accounting Bulletin No. 99 – Materiality In practice, thresholds tend to run somewhere between $1,000 and $25,000 depending on the organization’s size and the account. What auditors care about is consistency: apply the same threshold every period and document why you set it there.
Documentation and Retention
Every accrual needs backup. At minimum, attach the document supporting the estimate: purchase order, contract, rate schedule, calculation spreadsheet. For utility accruals based on historical averages, include the data behind the average. For payroll, show the proration formula and the pay period dates. Store the backup in a system tied to the journal entry so anyone reviewing the books can trace from the financial statement line item to the source.
IRS record retention depends on the situation, and the commonly cited “seven years” is only part of it:
- Three years is the general rule for most tax records, measured from the return’s filing date.
- Six years applies if you omit more than 25% of gross income from a return.
- Seven years applies if you claim a deduction for bad debt or worthless securities.
- Indefinite retention applies if you file a fraudulent return or don’t file at all.
Employment tax records must be kept for at least four years after the tax is due or paid, whichever is later.3Internal Revenue Service. How Long Should I Keep Records Because accrual entries often touch payroll and complex estimates spanning multiple retention categories, keeping records longer than the minimum is usually the sensible call.
Tax Timing Rules Are Not the Same as GAAP
Booking an accrual for financial reporting does not automatically make it deductible on the tax return. The IRS has its own timing rules, and in places they are stricter than GAAP.
An accrual-method taxpayer can deduct an expense only when three conditions are met: all events establishing the liability have occurred, the amount can be determined with reasonable accuracy, and economic performance has taken place.4Office of the Law Revision Counsel. 26 USC 461 – General Rule for Taxable Year of Deduction Economic performance generally means the other party has actually provided the services or delivered the property. Accruing an expense in December for services a vendor won’t perform until February fails this test, signed contract or not.
Recurring Item Exception
There is a carve-out for routine, predictable costs. Under the recurring item exception, an accrued expense can be deducted in the current year even if economic performance hasn’t happened yet, provided four conditions are met:
- The all events test is satisfied: fact and amount of the liability are established by year-end.
- Economic performance occurs by the earlier of the tax return filing date (including extensions) or 8½ months after the tax year closes.
- The liability is one you reasonably expect to incur year after year.
- The amount is either immaterial, or accruing it in the current year produces better matching of expense to related income.
The exception covers many bread-and-butter accruals: utilities, rent, insurance premiums, recurring professional fees.5eCFR. 26 CFR 1.461-5 – Recurring Item Exception It does not apply to liabilities for interest, workers’ compensation, tort claims, breach of contract, or violations of law.
Get the cycle right — identify, estimate, debit-expense-credit-liability, reverse on day one, keep the backup — and month-end stops being a scramble. The tax layer runs alongside it: what you accrue on the books may or may not deduct in the same year, and knowing which side of that line each item falls on is worth checking before you file.