S-Corp Accountable Plan: Deduct Home Office and Mileage in 2026

When you operate as a sole proprietor, your home office, mileage, and supplies land on Schedule C and reduce both your income tax and your self-employment tax. The S-Corp election changes the plumbing. Your business income now runs through Form 1120-S, you are an employee of your own company, and the personal deductions you used to take simply have nowhere to go. The fix is mechanical, cheap, and routinely missed.

The deduction you used to take is gone

Until 2017, an employee could deduct unreimbursed business expenses on Form 2106 as a miscellaneous itemized deduction subject to a 2% floor. The 2017 tax law suspended that deduction, and the 2025 One Big Beautiful Bill Act made the suspension permanent under IRC §67(g). The temporary rule that many people expected to expire after 2025 is now the permanent rule. For an S-Corp shareholder-employee, that means the home office, the mileage, the cell phone, and the software you pay for personally produce no deduction at all on your Form 1040.

Why an S-Corp owner can't just write it off

An S-Corp shareholder-employee files no Schedule C, and the One Big Beautiful Bill Act made permanent the suspension of miscellaneous itemized deductions, so Form 2106 unreimbursed employee expenses are gone for good. The only way to get a deduction for the home office is to have the S-Corp reimburse the owner for the business-use share of the home under an accountable plan. The reimbursement is then deductible on the 1120-S. This is different from a partnership, where a partner can sometimes deduct unreimbursed partnership expenses directly. S-Corp owners do not get that route, so the reimbursement is not optional housekeeping, it is the entire deduction.

What an accountable plan actually is

An accountable plan is a reimbursement arrangement that meets three rules in Treasury Regulation §1.62-2: the expense has a business connection, the employee substantiates it within a reasonable time, and the employee returns any excess advance. Meet all three and the reimbursement is deductible by the S-Corp and excluded from the employee's wages, so it never hits the W-2 and carries no payroll tax. Miss any one and the whole payment becomes taxable wages. The authority is IRC §62(a)(2)(A), which lets the reimbursement bypass the employee's income entirely instead of running through the salary line.

A reimbursement that satisfies Reg §1.62-2 is not reported on the owner's W-2, is not subject to income tax, and is not subject to Social Security or Medicare tax. It is simply a deductible business expense to the S-Corp. That is the advantage over a salary increase, which would carry both income and payroll tax.

What you can reimburse, and how to size it

The home office reimbursement is built on IRC §280A. The room must be used regularly and exclusively for business and must be the principal place of business or used for the convenience of the employer. You then reimburse the business-use percentage of the home's actual operating costs: utilities, insurance, repairs, depreciation, and the like. A 200 square foot office in a 2,000 square foot home is 10% of the space, so 10% of those costs are reimbursable. The $5 per square foot simplified method exists only for taxpayers claiming the deduction on their own return, so for an accountable plan you use the actual-expense method and keep the worksheet.

Mileage is the other big one. The 2026 IRS standard mileage rate for business use is 72.5 cents per mile, set in Notice 2026-10, up from 70 cents in 2025. An S-Corp can reimburse the owner-employee at that rate for documented business miles under an accountable plan, and the reimbursement is deductible to the company and tax-free to the owner. The owner must keep a contemporaneous mileage log showing date, destination, and business purpose. Add the business share of a cell phone and home internet, and the numbers add up faster than most owners expect.

What it is worth: a theoretical breakdown

Take a single-owner S-Corp with the facts below. None of these costs would produce any federal deduction without the plan, because the owner cannot deduct them personally. With the plan, every dollar is an ordinary business deduction on the 1120-S. The figures are illustrative and rounded.

At a 24% federal marginal rate, the $6,450 deduction is worth roughly $1,550 a year, and a state income tax stacks more on top. One honest caveat: the reimbursement also reduces qualified business income, so if you claim the §199A QBI deduction it claws back about a fifth of the benefit. The net savings are still real, they recur every year, and the cost to set the plan up is close to nothing.

How to set it up

Adopt a short written accountable plan policy, have the owner submit a monthly or quarterly expense report with receipts and a mileage log, and cut a separate reimbursement check from the business account that is not run through payroll. Keep the reimbursement off the W-2 and book it as a business expense on the 1120-S. The plan should be in place before the expenses are incurred, so set it up early in the year rather than scrambling at filing time. Do not reimburse with a round number every month and call it a day, because a flat allowance with no substantiation is the classic way an accountable plan gets recharacterized as wages on audit.

The accountable plan is one of the few S-Corp moves that costs nothing and pays every year. If you are still deciding whether the election makes sense in the first place, run the EntityIQ S-Corp tax calculator to see your self-employment tax savings, then layer the reimbursement deductions on top. For the salary side of the equation, see our guide on S-Corp reasonable compensation, and for owner health coverage see the 2% shareholder health insurance rules.

This article is educational and is not legal or tax advice. The figures above are 2026 amounts, and the owner is theoretical. Please consult a qualified CPA or EA before adopting an accountable plan or filing an S-Corp election.