How to Fill Out and Submit a Gas Reimbursement Form

A gas reimbursement form is the document you give your employer to get paid back for using your personal vehicle on company business. The math is simple: multiply your business miles by the IRS standard mileage rate (72.5 cents per mile for 2026) and submit the total for approval.¹ What determines whether that reimbursement arrives tax-free is everything surrounding the form: which miles you claim, what records back them up, and how your employer’s plan is structured.

What Goes on the Form

Whether your company uses a paper template, a shared spreadsheet, or an expense app like Concur or Expensify, the fields are the same. For each trip, record:

The date.
The destination — city, town, or specific address.
The business purpose, written specifically: “client meeting with Acme Corp” or “delivered supplies to warehouse,” not “business.”
Odometer start and stop readings, or the total miles driven.
Any tolls or parking paid out of pocket, if your employer reimburses those separately.

When a trip has multiple stops, list each leg on its own line with its own purpose. A drive from your office to a client site and then to a supplier is two segments, and lumping them together invites the kind of question that stalls your form in review.

The calculation is one step. Total business miles times the current IRS rate. A 45-mile round trip to a client comes out to $32.63 at the 2026 rate.¹ The rate applies to cars, vans, pickups, and panel trucks, including electric and hybrid vehicles. Some employers set their own per-mile rate above or below the IRS figure; the IRS rate is what matters for the tax treatment of the payment.

Which Miles Actually Count

This is where most forms run into trouble. Not every work-related drive qualifies, and the finance team will reject miles the IRS would disallow.

Your daily commute is never reimbursable. The drive from home to your regular office and back is a personal expense in the IRS’s view, regardless of distance or whether you took work calls along the way.² Once you’ve arrived at your regular workplace, any further driving to another business location — a client, a second company site, a supply store — is business mileage.

Two exceptions expand what you can claim:

If you have a regular office but drive to a temporary work site, the round trip from home to that temporary location counts.
If your home office qualifies under IRS rules as your principal place of business, every drive from home to another work location in the same trade or business counts as business mileage, not commuting.²

So if you work from home three days a week and drive to a client on Thursday, the whole round trip is reimbursable if your home office meets the IRS threshold. If it doesn’t, the drive to and from your first and last business stop of the day gets treated as a personal commute.

The Log That Backs Up the Form

The form is the request. The log is the proof. Under 26 CFR 1.274-5, the IRS requires “adequate records” for vehicle expenses, meaning documentation created at or near the time of travel rather than reconstructed from memory later.³ Reconstructed logs tend to stand out: the handwriting is too uniform, the mileage figures too round, the timestamps too neat.

For every trip, the log needs four things: the miles driven, the date, the destination, and the business purpose.² Odometer readings at the start and end of the year establish total annual mileage. A paper notebook works. So does a spreadsheet. GPS-based mileage apps work best because the time-stamped data is harder to challenge than anything handwritten.

Keep the records for at least three years from the filing date of the return that uses them.⁴ The IRS recommends four years for records tied to employment taxes, which includes employer reimbursements.⁵

Why the Plan Type Determines Your Taxes

Whether your reimbursement shows up on your W-2 depends entirely on how your employer structures its plan. The IRS splits reimbursement arrangements into two categories, and the difference costs real money.

An accountable plan meets three tests under 26 CFR 1.62-2:⁶

Business connection. The reimbursement covers only work-related expenses.
Substantiation. You provide adequate records within a reasonable time. The IRS safe harbor is 60 days after the expense.
Return of excess. If you got an advance larger than your actual expenses, you return the difference within 120 days.

When all three tests are met, the reimbursement is not reported as wages, is not on your W-2, and is exempt from income tax and payroll tax withholding.⁷ Most mid-size and large employers run accountable plans because they save payroll tax, too.

If any test fails — you don’t submit records, you keep an excess advance, the employer doesn’t require substantiation — the whole arrangement becomes a non-accountable plan. Those payments are taxable wages, included on your W-2 and subject to federal income tax withholding plus Social Security and Medicare.⁸ That turns a 72.5-cent reimbursement into something closer to 50 cents after withholding, depending on your bracket.

When an employer reimburses at or below the IRS standard rate, the per-mile dollar amount is “deemed substantiated,” meaning the employer doesn’t have to verify your actual vehicle costs.⁷ You still have to substantiate the miles, dates, and purposes of each trip. The shortcut covers the rate, not the trip.

Submitting the Form and Getting Paid

Procedures vary, but the workflow is close to universal. Fill out the form with your trip details and total, attach or link the mileage log, and route it to the approver — usually your direct supervisor first, then payroll or accounting.

Larger companies run everything through expense software: you enter trips, the platform applies the per-mile rate, and approvals move digitally. Smaller shops may use a shared spreadsheet or a fillable PDF emailed to a manager. The substantiation requirement is identical either way.

Most employers process reimbursements on the regular payroll cycle, so expect payment within one or two pay periods after approval. The amount usually appears as a separate line on your pay stub, distinct from wages, or lands as its own direct deposit. If your pay stub combines the reimbursement with wages and withholds taxes on it, that’s a sign the employer is running a non-accountable plan, and it’s worth asking HR about.

Mistakes That Delay Payment

Finance teams see the same errors over and over, and any of them can bounce the form back:

Claiming commuting miles. The drive from home to your regular office is not reimbursable. A log that shows the same home-to-office route daily will flag the whole form.
Vague business purposes. “Meeting” or “errands” doesn’t pass review. Name the client, project, or task.
Round-number odometer readings. A log full of 50s, 30s, and 25s reads as estimated. Record actual numbers.
Submitting late. The 60-day safe harbor is the practical deadline under an accountable plan. Miss it and the reimbursement can be reclassified as taxable income.
Using last year’s rate. The IRS updates the rate annually. For 2026 it’s 72.5 cents per mile, not the 70 cents that applied in 2025.

The fastest path to a clean payment is to log each trip the day it happens, submit the form weekly or biweekly rather than at month’s end, and verify your totals against your odometer math before sending.

If Your Employer Doesn’t Reimburse

Federal law does not require employers to reimburse mileage. Some states do, including California and Illinois, which mandate reimbursement for necessary business expenses. What federal law does set is a floor: under the Fair Labor Standards Act’s “kickback rule” at 29 CFR 531.35, if unreimbursed vehicle expenses push your effective hourly pay below the federal minimum wage, the employer is in violation.⁹ The rule treats required job costs an employer refuses to cover as an indirect kickback of wages, and it matters most for delivery drivers and field workers whose fuel and maintenance costs are large relative to pay.

For W-2 employees who aren’t reimbursed and don’t fall under a state mandate, the tax picture tightened after 2017. The Tax Cuts and Jobs Act suspended the miscellaneous itemized deduction for unreimbursed employee expenses through 2025, so most W-2 employees who pay out of pocket for business driving absorb the cost.¹⁰

1
Internal Revenue Service. IRS Sets 2026 Business Standard Mileage Rate at 72.5 Cents per Mile, Up 2.5 Cents
2
Internal Revenue Service. Publication 463 (2025), Travel, Gift, and Car Expenses
3
eCFR. 26 CFR 1.274-5 – Substantiation Requirements
4
Internal Revenue Service. How Long Should I Keep Records
5
Internal Revenue Service. Recordkeeping
6
eCFR. 26 CFR 1.62-2 – Reimbursements and Other Expense Allowance Arrangements
7
Internal Revenue Service. Rev. Proc. 2019-46
8
Internal Revenue Service. Internal Revenue Service Fringe Benefit Guide
9
eCFR. 29 CFR 531.35
10
Internal Revenue Service. Topic No. 511, Business Travel Expenses