What per diem covers
Per diem is a daily allowance method for substantiating eligible travel expenses, including meals and incidental expenses, when a taxpayer is away from their tax home for business. It does not replace the need to establish the business travel itself.
Use the current transportation-industry rate
The IRS publishes special meals and incidental expense rates for qualifying transportation-industry workers. Because rates and effective dates can change, use the current IRS notice or review the rate that applies to your travel period instead of relying on a projected figure.
Eligibility depends on the travel facts
Eligibility is not determined by job title alone. The tax-home rules, overnight travel, work arrangement, reimbursements, and the details of each trip all matter. Keep dispatch, trip, and lodging records that support the travel away from home.
Keep travel records
Maintain dates, destinations, business purpose, and supporting trip records. A clear log makes it easier to determine which expenses and substantiation method may apply.
Review the tax treatment before filing
The treatment of reimbursements and unreimbursed expenses can differ for employees and self-employed drivers. Review the current rules for your circumstances before taking a deduction or treating a payment as non-taxable.