Rules
Mileage Deduction Records When Two Preparers Split Your Return
Mileage deduction records when two preparers split your return: build one dated log, share it, and keep the deduction on a single Schedule C.
What to take away
- One vehicle needs one mileage log. Two preparers should read the same dated record instead of rebuilding it.
- IRS Publication 463 expects date, destination, business purpose and miles for each business trip.
- The preparer who files your Schedule C claims the mileage, unless an entity owns the vehicle.
- Assign one preparer to own the vehicle expense and confirm that split in writing before either return is filed.
- Rates and state conformity rules change the total. They never change the log.
Who claims mileage when two preparers share a return
A split return usually means an entity return plus a personal return. One preparer handles Form 1065 or Form 1120-S. The other handles your Form 1040 and Schedule C.
Vehicle title answers the first question. A car you own personally produces a Schedule C deduction. A car titled to the corporation belongs to the corporation.
When the entity titles the car, the split K-1 services question decides who deducts what and which preparer signs which return.
Building one mileage log that serves both preparers
A defensible log carries five fields. Build it once, then share a read only copy with each preparer.
Five Fields Every Mileage Log Needs
- Dateday the trip happened
- Destinationaddress or client name
- Purposespecific business reason
- Milestrip miles or odometer start/end
- Categoryclient visit, supply run, airport, other
Building one mileage log
- Date
- The day the trip happened
- Destination
- Address or client name
- Purpose
- The specific business reason
- Miles
- Trip miles or odometer start and end
- Category
- Client visit, supply run, airport, other
Your expense method locks in with the first year you claim the vehicle. Standard mileage and actual expenses produce different numbers. IRS Publication 463 explains when each method applies and how switching works.
Take a January 1 and December 31 odometer photo. That total proves the business percentage both preparers will report.
Log handoff between preparers
- Name one preparer as the vehicle expense owner in an email both can read.
- Send the same file version to both, with the date in the file name.
- List every trip the other preparer already counted so nothing is claimed twice.
- Ask the personal preparer to confirm the business percentage in writing.
- Save that confirmation beside the log for the next filing season.
Two preparers can divide the work. They cannot deduct the same 5,000 business miles twice.
Log Handoff Between Two Preparers
- Name one preparer as vehicle expense owner
- Send same file version to both preparers
- List trips the other preparer already counted
- Get business percentage confirmed in writing
- Save confirmation beside the log
Example: one van, two preparers, one deduction
A consultant drives 18,000 miles in a van she owns personally and logs 12,000 of them as business. Her S corporation preparer files Form 1120-S and checks that no accountable plan reimbursement exists. Her personal preparer files Schedule C and claims the 12,000 miles.
The corporation reimburses nothing, so the deduction stays on Schedule C. Had it reimbursed her under an accountable plan, the corporation would take the deduction and the payment would be excluded from her income.
Business use percentage drives the number, and IRS Tax Topic 510 shows how the standard mileage method compares with actual expenses.
When the drive crosses a national border
Trips into Canada add currency and distance units. Track kilometres and the exchange rate you applied on each date rather than one average rate.
The Canada Revenue Agency publishes motor vehicle expense rules and per kilometre allowance rates for sole proprietors.
A treaty position, a currency conversion and a Schedule C line all interact, so the cross-border mileage guide walks through each step.
When the drive crosses a state line
California starts from federal figures but does not conform to every federal rule. Texas has no personal income tax, so the federal Schedule C deduction carries through there.
Apportionment matters when you work in both states, and the California and Texas business mileage page covers conformity, apportionment and the Schedule C line.
The return follows the entity
A sole proprietor files Schedule C with Form 1040. A partnership files Form 1065. An S corporation files Form 1120-S.
Every figure you hand a preparer carries a tax year, and the federal business tax overview explains which return follows which entity and why that year label matters.
