An accountable plan is an employer’s rules for paying back work costs that employees cover themselves, set up so the IRS treats the money as a repayment, not pay. When the plan meets three conditions, the reimbursements carry no income tax, no Social Security and no Medicare, and they never appear on the employee’s W-2.
Miss any condition and the same dollars become wages. The rest of this guide shows what that costs with real numbers, the three conditions in plain terms, how per-mile allowances fit in, and how a small business can set a plan up without a lawyer.
Same car, same miles, three ways to pay
Take an invented outside estimator at a San Antonio roofing company. They drive their own car between job sites, about 600 business miles a month. Texas has no state income tax, so every difference below comes from federal withholding and payroll tax. Here is one month, July, paid three different ways:
| Accountable plan: logged miles at the IRS rate | Allowance of 85 cents a logged mile | Flat car allowance, no mileage log | |
|---|---|---|---|
| Paid to the estimator | $456.00 | $510.00 | $456.00 |
| Treated as wages | $0.00 | $54.00 | $456.00 |
| Federal income tax withheld (22% flat rate) | $0.00 | $11.88 | $100.32 |
| Social Security withheld | $0.00 | $3.35 | $28.27 |
| Medicare withheld | $0.00 | $0.78 | $6.61 |
| Estimator keeps | $456.00 | $493.99 | $320.80 |
| Employer's matching Social Security and Medicare | $0.00 | $4.13 | $34.88 |
| On the W-2 | Nothing | $54.00 in boxes 1, 3 and 5; $456.00 in box 12, code L | $456.00 in boxes 1, 3 and 5 |
The first column is the accountable plan: the estimator logs each trip and is repaid at the IRS business rate. Nothing is withheld because nothing is wages. The third column pays the same dollars as a flat car allowance with no log, and that one change turns the whole amount into supplemental pay.
Supplemental pay can be withheld at the optional flat rate of 22%, and Social Security at 6.20% and Medicare at 1.45% come out on top. The employer then matches both payroll taxes from its own pocket. The estimator’s car costs did not change; only the paperwork did.
Over a full year
Across twelve months the gap stops being small change. The flat allowance costs the employee a sizable share of the money and costs the employer its matching tax as well, plus federal unemployment tax while the worker’s pay is still under the $7,000 FUTA wage base.
The three rules an accountable plan must meet
The rules come from Treasury regulation 26 CFR 1.62-2 and are repeated in IRS Publication 15. A plan has to require all three; a policy that merely allows them does not count.
| Rule | What it requires | What to keep |
|---|---|---|
| Business connection | The money pays for costs of doing the job, not something the employee would have been paid anyway | A written policy naming the costs it covers |
| Substantiation | The employee accounts for each cost: amount, date, place and business purpose | Receipts, a mileage log or an expense report |
| Return of excess | Any advance or allowance beyond what was accounted for goes back | A ledger of advances and repayments |
| Timing, option 1 | Advance within 30 days of the cost, account within 60 days after it, return excess within 120 days after it | Dated reports and payments |
| Timing, option 2 | The employer sends a statement at least once a quarter; the employee accounts or repays within 120 days of it | Copies of each statement |
Business connection means the money matches real costs of doing the job. Paying an allowance whether or not the employee spends anything fails here, and so does relabeling part of a salary as a reimbursement. The IRS says a payment that would otherwise have been wages cannot be turned into a reimbursement.
Substantiation means accounting for each cost: the amount, the date, the place and the business reason. For most purchases that is a receipt plus a line on an expense report. For driving, a mileage log replaces the receipt, because the per-mile rate stands in for fuel, wear and insurance.
Returning the excess applies to advances and allowances. If the company hands over money up front and the employee spends less, the difference goes back. Keeping it is fine only if the employer treats the leftover as wages and taxes it.
Picking a timing method
“A reasonable period” is a facts-and-circumstances test, so the regulation offers two safe harbors. The fixed date method counts from each expense: advance within 30 days, account within 60 days, return any excess within 120 days. Most small businesses use this one because an expense report already carries the dates.
The periodic statement method suits companies that hand out regular advances. At least once a quarter, the employer sends each person a statement of what is still unaccounted for, and the employee has 120 days from that statement to document it or pay it back.
Per diem and per-mile allowances
An employer does not have to repay actual costs. It can pay a fixed amount per mile or per travel day instead, and the employee is treated as having accounted for the money as long as the rate stays within the federal one.
The employee still has to prove the trip itself: the date, the destination, the purpose and the miles.
The middle column shows a company paying more than the federal rate. The part up to the IRS rate stays tax-free; only the excess is wages.
On the W-2, the excess goes in boxes 1, 3 and 5, and the tax-free part is reported in box 12 with code L. Our list of W-2 box 12 codes explains the rest.
The IRS rate changed partway through 2026, so trips are paid at the rate in force on their date. Our page on the 2026 IRS mileage rate gives both rates and the July 1 switch. Meal and lodging allowances follow the federal per diem rates published by the General Services Administration.
Accountable vs nonaccountable plan: what tips it over
- No records asked for. A monthly phone or car stipend with no log or bill behind it is a nonaccountable payment from the start.
- Late reports. Amounts documented after the safe-harbor window become wages in the first payroll after the window closes.
- Advances never trued up. Leftover cash an employee keeps must be run through payroll as taxable pay.
- A pattern of abuse. If the employer routinely ignores its own rules, the regulation treats every payment under the arrangement as nonaccountable, not just the bad ones.
Nonaccountable money cannot be fixed later by the employee. Under the regulation, a worker paid under a nonaccountable plan cannot make it accountable by turning in receipts after the fact. The repair has to happen in the employer’s policy, going forward.
Employees also lose their fallback. IRS Publication 529 says most workers can no longer deduct unreimbursed job expenses on their own return; only 4 groups still can, such as Armed Forces reservists. For everyone else, an accountable plan is the only way work costs come back untaxed.
Setting one up in a small business
- Write it down. One page is enough: which costs are covered, how to request repayment, the deadlines, and that unspent advances must come back. The regulation does not demand a written plan, but a written one is far easier to prove.
- Pick the timing method and put the day counts in the policy.
- Give people a form. Our free expense report template applies the IRS mileage rate by trip date and exports to Excel.
- Pay reimbursements as their own line. If they ride along with a paycheck, the regulation requires the amount to be identified separately, so it never mixes with wages.
- Review once a year. Check that reports came in on time and that leftover advances were repaid or taxed.
On a pay stub, an accountable plan repayment shows up below net pay, untaxed, often marked REIMB. Our pay stub generator has a separate reimbursement field for exactly this, so it never inflates gross pay or withholding.
Do owners of S corporations use them?
Yes. An owner who works in their own S corporation is an employee of it, so the same rules apply. A home office share, a phone or business miles in a personal car can be repaid tax-free if the owner documents them like any other employee would.
Sole proprietors and single-member LLC owners taxed as sole proprietors are different. They are not employees of their own business, so there is nothing to reimburse; they deduct the costs on their own return instead. A contractor billing a client for costs puts them on an invoice.
Sources: 26 CFR 1.62-2, reimbursements and other expense allowance arrangements; IRS Publication 15 (2026), section 5 and section 7; IRS Publication 529; IRS standard mileage rates for each half of 2026. Example amounts from our payroll tax engine. Checked October 29, 2026.
