How do mileage reimbursement and vehicle allowance arrangements for employees and contractors work (per-mile/standard rate, fixed allowance, fixed-and-variable rate), and what mileage records substantiate them? Worker class and year tokens are modifiers and must not be split into separate candidates.

How does each structure compute the payment?

The IRS's Rev. Proc. 2019-46 provides rules for substantiating the employee driving costs that a payer (an employer, its agent or a third party) reimburses with a mileage allowance. It defines that as a payment for the business transportation costs an employee incurs, or is expected to incur, in performing services as an employee, reasonably calculated not to exceed them, and paid at the standard mileage rate, a flat rate or stated schedule, or another IRS-specified rate. A flat rate may be paid periodically at a fixed rate, a cents-per-mile rate, a variable schedule or a combination, but must be paid on a uniform and objective basis. Rev. Proc. 2019-46's mileage-allowance method is optional: it lets actual allowable expenses be substantiated instead with adequate records or other sufficient evidence, which is a separate question.

Rev. Proc. 2019-46 defines a FAVR allowance as periodic fixed and variable payments that meet all the requirements of its section 6. Having both parts is not enough: the procedure tests a fixed-plus-per-mile allowance that misses section 6 like any other fixed allowance.

When is a payment to an employee a reimbursement rather than pay?

The IRS's Rev. Proc. 2019-46 sets three requirements for an accountable plan: business connection, substantiation, and returning amounts in excess of expenses. Under the procedure, amounts paid under an arrangement meeting all three are excluded from income and wages; if it misses one or more, all amounts under it are nonaccountable: included in the employee's income as wages and subject to withholding. Rev. Proc. 2019-46 adds that an arrangement paying an employee regardless of whether they incur deductible business expenses fails the business-connection requirement, making everything under it nonaccountable.

Within an accountable plan, Rev. Proc. 2019-46 deems part of a mileage allowance substantiated:

• For any allowance other than FAVR, it is the lesser of the amount paid or the business standard mileage rate times the substantiated business miles.
• For FAVR, it is the amount paid, less variable payments for unsubstantiated miles and fixed payments for periods without coverage that the employee failed to return though required to, and less any optional high-mileage payments.

Under the procedure, the deeming works only if the employee actually substantiates to you the time, place (or use) and business purpose of the driving. The part up to the deemed amount is treated as paid under an accountable plan, if the plan's other requirements are met, and is exempt from withholding; the excess is nonaccountable and reported as wages. With no trip records no miles are substantiated, so an entire flat allowance is wages, whatever the plan calls it.

Publication 463 (2025 edition, for use in preparing 2025 returns) says a car allowance satisfies adequate accounting for the amount of expenses only if the employee is not related to you. Under Publication 463, an employee is related to you if you are their brother or sister, half brother or half sister, spouse, ancestor or lineal descendant; if you are a corporation in which they own, directly or indirectly, more than 10% in value of the outstanding stock; or if certain relationships, such as grantor, fiduciary or beneficiary, exist between them, a trust and you. A related employee must be able to prove expenses to the IRS even after accounting to you and returning any excess.

Publication 463 requires the employee to account to you and return any excess within a reasonable period, and treats the following actions as taking place within one, whatever the facts:

• An advance is paid within 30 days of the expense.
• The employee adequately accounts within 60 days after the expense was paid or incurred.
• The employee returns any excess within 120 days after the expense was paid or incurred.
• The employee receives a statement, at least quarterly, asking them to return or account for outstanding advances, and complies within 120 days of it.

Rev. Proc. 2019-46 sets the return rule and withholding deadline by structure:

Rev. Proc. 2019-46 treats every payment under a mileage allowance as nonaccountable if the arrangement shows a pattern of abuse, for example having no process to spot allowances above the deemed-substantiated amount while routinely paying such excess without requiring substantiation or repayment, or treating it as wages.

Which rate applies to the period the driving happened in?

The IRS publishes the business standard mileage rate in an annual notice, based on an annual study of the fixed and variable costs of operating an automobile that an independent contractor performs for it. Notice 2026-10 set the 2026 business rate at 72.5 cents per mile and says taxpayers using the rates must comply with Rev. Proc. 2019-46, except where the One, Big, Beautiful Bill Act specifically changed the law. Announcement 2026-11 raised the business rate to 76 cents per mile from July 1, 2026, assigning the rate by payment date and driving date:

Notice 2026-10's rate is for 2026; for driving before January 1, 2026, confirm the rate in the IRS notice for that period before paying. For an allowance paid on or after July 1, split the period's miles by trip date. A rate from the wrong period mis-states every payment: reimbursing June miles at 76 cents in July pays 3.5 cents a mile above the applicable rate, and that excess is wages. The announcement left Notice 2026-10's other provisions in effect, including the FAVR cap: for 2026 the standard automobile cost may not exceed $61,700 for automobiles, including trucks and vans.

What must a FAVR plan be built on, and who can run one?

Under Rev. Proc. 2019-46, a FAVR allowance deems substantiated the costs of employees driving a car they own or lease, and only if every section 6 condition is met. A payer can run one directly or through an agent or third party, but only if its FAVR allowances cover at least five employees in total at all times during the calendar year. The plan must be built this way:

• Cost data. The amount must rest on data derived from the base locality that reflects retail prices paid by consumers and is reasonable and statistically defensible.
• Standard automobile. The payer selects the car the allowance is based on, and its cost for a calendar year may not exceed 95 percent of the sum of the standard automobile's retail dealer invoice cost in the base locality and the state and local sales or use taxes on its purchase, nor $61,700 for 2026.
• Payments. A fixed payment covers projected fixed costs, including depreciation or lease payments, insurance, registration and license fees, and personal property taxes; a variable payment covers projected running costs, including gasoline and its taxes, oil, tires, and routine maintenance and repairs. Both must be paid at least quarterly, and the variable payment is made for each substantiated business mile at no more than the computation period's rate.
• Projections. Projected annual business mileage may not be less than 6,250 miles, the business use percentage may not exceed 75 percent, and the retention period may not be less than two calendar years.
• Insurance and depreciation. The insurance component must use base-locality rates for the standard automobile without rate-increasing factors such as poor driving records or young drivers. The depreciation component may not exceed the standard automobile cost minus its residual value, or the sum of the annual section 280F limits, unless annual FAVR payments to an employee driving 80 percent of the annual business mileage do not exceed the business standard rate times that mileage.

The payer may cover an employee only within these limits:

• Mileage. The employee must substantiate at least 5,000 business miles for the calendar year or, if greater, 80 percent of the plan's annual business mileage, prorated monthly for part-year coverage.
• Eligibility. No control employee, as defined in regulation section 1.61-21(f)(5) and (6) without its $100,000 limitation, may be covered, and no allowance may be paid if at any time in a calendar year most covered employees are management employees.
• The car. The employee must own or lease it, its cost as a new vehicle must be at least 90 percent of the standard automobile cost used in the first year of coverage, and its model year may not differ from the current year by more than the years in the retention period. It may not be a leased car for which the employee used actual expenses in any lease year, or a car on which the employee claimed non-straight-line depreciation, a section 179 deduction, the additional first-year depreciation allowance, ACRS or MACRS.
• Insurance. The employee's coverage limits must at least equal those used to compute the fixed payment.

Within 30 days after coverage starts or resumes, the employee must give a written declaration of the car's make, model and year, proof of insurance limits, the odometer reading, the purchase price (or, if leased, the gross capitalized cost) and its depreciation or actual-expense history, and must repeat the first three within 30 days after each calendar year begins. The payer or its agent must keep written records of the statistical data and projections behind the payments and of those declarations, and within 30 days after each year ends must give each covered employee a statement listing the depreciation in each fixed payment. Rev. Proc. 2019-46 requires that statement to explain, for an owner, that by receiving the allowance the employee has elected to exclude the car from MACRS under section 168(f)(1) and, for a lessee, that the employee may not compute the car's deductible business expenses using actual expenses for the lease period.

If an allowance fails any requirement of Rev. Proc. 2019-46's section 6, including a payer-level one such as the five-employee minimum, the employee is not treated as covered by any FAVR allowance for the period of the failure. The procedure's standard-rate method in sections 4, 7.01(1) and 7.02 may still apply to the extent its requirements are met.

What must each trip record contain, and who captures it when?

Publication 463's table of required records lists, for car expenses, the date of use, the business destination, the business purpose, the mileage for each business use and the total miles for the year. The employee adequately accounts by giving you a statement, account book, diary or similar record in which each expense was entered at or near the time. Publication 463 says to record a business use at or near the time of the use and accepts a log kept weekly as timely. A log rebuilt later from a calendar or memory was not entered at or near the time, so it does not meet Publication 463's definition of adequately accounting to you. Require logging at the trip or weekly, and do not accept a rebuilt log as the plan's adequate accounting. Publication 463 adds that a timely kept record has more value than a statement prepared later, when accurate recall is generally lacking. It also accepts a computer record and lets one record cover a round trip or uninterrupted business use.

The same fields serve employees and contractors:

For a contractor, the substantiation regulation, 26 CFR 1.274-5T, requires the contractor to substantiate each element and sets no deadline for giving the record to you.

Where the car is also used personally, only substantiated business miles enter the deemed amount, so the log must separate business miles from total use rather than record the car's total alone. Which trips count as business mileage, including commuting and travel from a home base, is a separate question.

How do you compare what you paid with what the log supports?

Run the comparison every pay period, and at least quarterly for a fixed allowance:

1. Total the substantiated business miles for the period, split by rate period.
2. Multiply each block by its rate; for FAVR, use the FAVR deemed amount instead.
3. Total what you paid for the same period.
4. Compare the two and act on the result.

For example, an employee receives a fixed allowance of 600.00 on the last day of each month from July through September 2026 and logs 610, 540 and 450 business miles in those months. Every payment and every mile falls on or after July 1, so 76 cents applies.

Rev. Proc. 2019-46 requires the plan to call for return of the 584.00 within a reasonable period and makes the excess subject to withholding no later than the first payroll period after the one in which you computed it. The procedure does not say how a repayment made within the plan's reasonable period, but after that payroll, interacts with the withholding deadline. The conservative course is to recover the excess before that payroll or withhold on it in that payroll; confirm how to treat a later repayment with a tax professional.

How is the payment reported for an employee and for a contractor?

Whether a driver is an employee or a contractor is a separate determination; the trip record is the same either way, and only the reporting differs. For an employee, the substantiated part paid under an accountable plan is not wages; the excess, and everything paid under a nonaccountable plan, is wages. The IRS's Form 1099 instructions say not to use Form 1099-NEC for employee business expense reimbursements. The same instructions say accountable-plan payments are generally not reportable on Form W-2, except in certain cases when you pay a per diem or mileage allowance, so check how your mileage allowance is reported on the W-2. W-2 and payroll handling are separate questions.

Rev. Proc. 2019-46 writes its mileage-allowance rules for employees and counts passenger automobiles as listed property. For an independent contractor, the substantiation regulation, 26 CFR 1.274-5T, requires a contractor reimbursed by a client to substantiate each element of the expense, a rule that covers listed property, and to include in income any reimbursement not substantiated. The contractor therefore keeps the trip record. The Instructions for Forms 1099-MISC and 1099-NEC (12/2026) say you must generally report a payment as nonemployee compensation if all four conditions are met:

• You paid someone who is not your employee.
• You paid for services in the course of your trade or business, including government agencies and nonprofit organizations.
• You paid an individual, partnership, estate or, in some cases, a corporation.
• You paid the payee at least $2,000 during the year, the threshold for tax years beginning after 2025.

Those instructions do not say whether a mileage reimbursement the contractor has substantiated counts toward that total, so settle its treatment with a tax professional before filing.

How long should the records and calculations be kept?

The IRS's Publication 15 (2026) tells employers to keep all records of employment taxes for at least 4 years and have them available for IRS review. The logs and period computations decide which part of each allowance was wages, so keep them with those records at least as long.

What should the written arrangement say?

Publication 463 says an employer should tell employees what method of reimbursement is used and what records they must provide. FAVR requires written declarations and records; for any structure, a written policy is what shows which structure each payment belonged to and how it was computed. It should state:

• The structure, the rate or amount, and how each payment is computed
• The rate basis, meaning the IRS rate that fits both the payment date and the driving date under the IRS notice or announcement for that period
• The trip-record fields, how drivers submit them and by when
• The duty to return any excess, and the deadline
• How often you compare payments with substantiated amounts
• For FAVR, the standard automobile, base locality, data source and retention period

What if your state has its own reimbursement rule?

A state can impose its own duty to reimburse employees, decided under that state's law and separately from the federal treatment. California Labor Code section 2802, for example, requires an employer to indemnify an employee for all necessary expenditures or losses incurred in direct consequence of the discharge of their duties. Meeting the federal rules does not show a state duty is met. Section 2802, for instance, measures the duty by the employee's necessary expenditures or losses, not by the IRS rate, so paying the federal substantiated amount, or more, does not by itself show that duty is met. Check your own state's statute or labor agency.