Driving Your Own Car to Canada or Mexico for Business: Mileage Log, Kilometers to Miles and Foreign Toll Receipts (2026)

Published: October 27, 2026 · Reading time: 12 min

TL;DR: If you drive your own car across the Canadian or Mexican border for a client, the IRS splits the trip at the border. Publication 463 says travel by private car in the United States is travel between points in the United States, even on the way to a destination outside it, so the drive from home to the border follows the ordinary rules and only the part beyond the border falls under the foreign-travel rules. Log the two parts separately with odometer readings at each crossing, convert kilometers to miles by dividing by 1.609344, and value the miles at the rate for the date of each trip (72.5 cents for January 1 to June 30, 2026 and 76 cents from July 1). Tolls and business parking are deductible on top of the standard rate; fuel is not, because the standard rate already includes it. Foreign receipts must end up in U.S. dollars. In the worked example below, a five-day September trip comes to 400.6 business miles, $304.46 of mileage and $348.84 with tolls and parking. Logging the kilometers as miles would have produced $467.78, an overstatement of $163.32.

Most mileage guides assume every mile is a domestic mile. The moment your route crosses a border, three questions appear that a domestic freelancer never faces: do the foreign miles count, what do you do with a log full of kilometers, and what do you do with a toll receipt in another currency?

This guide covers a self-employed freelancer filing a Schedule C who drives their own or leased car to a client in Canada or Mexico, such as a photographer shooting an event in Toronto, a consultant visiting a plant in Monterrey or a trade-show contractor setting up in Montreal. It covers federal income tax only. It does not cover customs, insurance requirements, visas or the other country's taxes, which depend on where you work and are outside this guide.

For the broader rules, see our foreign business trip guide, which covers the one-week and 25% exceptions in full, and our foreign receipts and currency conversion guide. This post covers the part those two leave out: the car.

The Border Splits the Trip: The Private-Car Rule

Publication 463 has a short paragraph written for exactly this case:

"Travel by private car in the United States is travel between points in the United States, even though you are on your way to a destination outside the United States."

It follows with an example:

"You travel by car from Denver to Mexico City and return. Your travel from Denver to the border and from the border back to Denver is travel in the United States, and the rules in this section apply. The rules below under Travel Outside the United States apply to your trip from the border to Mexico City and back to the border."

The regulation behind it, Treas. Reg. §1.274-4(e)(2)(ii), says the same thing about cars: "In the case of travel by private automobile, any such travel which is within the United States shall be considered travel from one point in the United States to another point in the United States". The same regulation says the domestic portion is disregarded when you test whether the trip lasted more than a week, whether personal time reached 25%, and how much expense is subject to allocation.

Two consequences follow for a driver:

1. The drive from your home to the border is ordinary business travel. If you are away from your tax home overnight on business, the car cost of getting to your destination is handled like any other domestic travel. The foreign-travel limits do not reach it. The tax home guide explains how to tell where your trip really starts.
2. Only the miles beyond the border are even candidates for the foreign-travel limits. And those limits only bite in one situation, covered below: a trip that is longer than a week with 25% or more personal time.

This is why the odometer reading at the border is the most important number on the page. It is the line the whole analysis is drawn along.

Two Logs in One: What to Record at Each Stage

The substantiation rules do not change because you crossed a border. Section 274(d) requires adequate records or sufficient evidence corroborating your own statement for listed property such as a car, and Treas. Reg. §1.274-5T(b)(6) names the elements: the amount of business use, measured in mileage for an automobile, the total use for the year, the date and the business purpose. Publication 463's recordkeeping table puts it in plain terms: "For car expenses, the cost of the car and any improvements, the date you started using it for business, the mileage for each business use, and the total miles for the year." The table also asks for your business destination and the business purpose.

For a cross-border drive, the log needs a few extra anchors:

Take the readings with a photo, because a photo is dated by your phone and is hard to dispute. Where you cross on a tolled bridge or tunnel, the toll receipt, where one exists, carries a date and is a second independent record of when you crossed. Our odometer readings guide and contemporaneous log requirements explain why records made at the time carry more weight than a log rebuilt in April, and our business purpose notes guide shows what to write in the purpose column.

Kilometers to Miles: Convert Once, From the Total

Road signs in Canada and Mexico are in kilometers, and so is the maps app you will use to find the client. The tax records you keep are in miles: the regulation's measure for an automobile is mileage and the IRS rate is a cents-per-mile figure. The conversion is exact:

NIST's conversion tables (SP 811, Appendix B) list the factor as 1.609 344 kilometers per mile, so there is no judgment in it. Three habits keep the conversion from becoming a problem:

• Convert the total, not every leg. Rounding each leg to a tenth of a mile and adding them gives a slightly different figure than converting the sum. Pick the total and round once, to one decimal place.
• Write the kilometer figure in the notes. If a preparer or examiner checks, the original number and the factor reproduce your result in seconds.
• Never enter kilometers in a miles field. The error is large and one-directional. A kilometer is only about 0.62 of a mile, so a log kept in kilometers and labeled miles overstates the deduction by roughly 61%. The worked example below shows it in dollars.

If your odometer reads only in kilometers (a rental or a car imported from abroad), convert the odometer readings before you subtract them. A dashboard that shows both units is easier: photograph the miles side.

A maps app and an odometer will not agree to the tenth. Our GPS and odometer discrepancy guide explains why small gaps are normal. The conservative habit is to claim the logged business legs, not the larger odometer difference, because the odometer also counts parking-lot loops and short moves you did not log.

Standard Rate or Actual Expenses When You Cross the Border

Both methods are available for a car you own or lease. The standard versus actual guide covers the choice in general. Four points matter for a cross-border drive.

The rate applies to business miles. Revenue Procedure 2019-46 §4.01 says a taxpayer generally may deduct "the business standard mileage rate times the number of business miles traveled" or the actual costs allocable to those miles. Neither that section nor the standard mileage section of Publication 463 draws a line at the border. The two rates for 2026 on the IRS standard mileage rates page are 72.5 cents per mile for January 1 to June 30 (IR-2025-128) and 76 cents per mile from July 1 (IR-2026-29). Value each trip at the rate for its date; our 2026 mileage rate guide covers the split. The IRS materials do not discuss foreign miles as such, so a CPA or EA should confirm your own facts.

The rate already includes fuel and insurance. Publication 463 says that if you use the standard mileage rate you can't deduct "depreciation, lease payments, maintenance and repairs, gasoline (including gasoline taxes), oil, insurance, or vehicle registration fees." Revenue Procedure 2019-46 §4.02 lists insurance and license and registration fees as items included in the rate. So the fuel you buy in Ontario and any separate short-term policy you buy for the trip are not extra deductions under the standard rate. Under actual expenses they are vehicle costs, claimed only for the business share.

Tolls and parking are added on top. Publication 463 says: "In addition to using the standard mileage rate, you can deduct any business-related parking fees and tolls." Parking at your regular place of work is still commuting. See our tolls and parking guide for the receipts.

A rental car is a different method. Publication 463 describes the standard rate for a car you own or lease. For a rental it says: "If you rent a car while away from home on business, you can deduct only the business-use portion of the expenses." The rental charge and fuel are what you track, with a receipt for each. See rental car and rideshare receipts.

You must also keep total miles for the year, foreign miles included. Business-use percentage is business miles divided by total miles, so leaving the foreign driving out of the total skews it.

Foreign Tolls, Parking and Fuel: Get Every Receipt Into Dollars

Publication 54 sets the rule for any expense paid in another currency:

"You must express the amounts you report on your U.S. tax return in U.S. dollars. If you receive all or part of your income, or pay some or all of your expenses, in foreign currency, you must translate the foreign currency into U.S. dollars."

For a freelancer paying by card, the card statement does the translation: the U.S. dollar amount that left your account is the cost, foreign transaction fee included. For cash, the habit is to write the rate and its source on the receipt and use one source for the whole trip. Our foreign currency receipts guide walks through both cases, including why a foreign-language receipt is still a valid receipt.

What to keep for a driving trip:

Electronic tolls are the easy one to lose. A transponder or plate-read toll may be billed weeks later by mail or email, in the local currency, so look for the statement and match it to the trip date before you file. See how to organize receipts for taxes.

When the Trip Isn't All Business

Personal driving abroad is not deductible, whatever the trip's length. The only question the foreign-travel rules add is how much of the cost of getting there and back survives when the trip mixes business and personal time. Publication 463 lists four situations that treat a trip as entirely business. Two matter most for a freelancer who arranged the trip themselves (the other two are narrower, and our foreign business trip guide covers them):

• Outside the United States a week or less. Publication 463 says the trip "is considered entirely for business if you were outside the United States for a week or less, combining business and nonbusiness activities." It adds: "One week means 7 consecutive days. In counting the days, don't count the day you leave the United States, but do count the day you return to the United States."
• More than a week, with less than 25% of the time on personal activities. Then the trip is also considered entirely for business.

Outside those exceptions, Publication 463 says you "must allocate your travel time on a day-to-day basis between business days and nonbusiness days," with the days you depart from and return to the United States both counted, and the deductible share of the round-trip travel expenses is business days over total days. Transportation days count as business days, but a detour for personal reasons does not stretch them. The regulation's own example involves a car: a taxpayer who drives from New York to Quebec for a meeting and spends 2 days in Ottawa and 1 in Montreal on personal activities counts only "that number of days outside the United States" as business days "as would have been required for the taxpayer to drive by a reasonably direct route to Quebec, taking into account normal periods for rest and meals."

For a driver, the cost of getting there and back is the car cost of the foreign part of the journey to your destination, because the domestic drive to the border is disregarded under Treas. Reg. §1.274-4(e)(1). The IRS materials I reviewed do not spell out an automobile computation for the standard rate, so the numbers in the extended-trip example below are one reasonable reading, not a ruling. Confirm it with a CPA or EA before relying on it. The full day-counting rules are in our foreign business trip guide, and the per diem versus actual guide covers the meals and lodging side.

Worked Example: A Five-Day Drive to Toronto

Marcus is a freelance event photographer near Buffalo, New York. He is a sole proprietor, drives his own car for work and uses the standard mileage rate. The facts below are assumed for illustration. In mid-September 2026 he drives to Toronto for three client shoots.

Facts. The trip runs Monday, September 14 to Friday, September 18, 2026. Home to the border crossing is 24.0 miles each way, on the U.S. side. His car's odometer reads 41,200.0 at home, 41,224.0 at the outbound border crossing, 41,596.5 at the return crossing and 41,620.5 at home. He uses a maps app in Canada, which gives kilometers.

Legs in Canada (kilometers from the maps app)

Conversion and mileage

• Business kilometers: 567.5 ÷ 1.609344 = 352.6 miles (rounded once, from the total)
• U.S. leg: 24.0 × 2 = 48.0 miles
• Business miles for the trip: 352.6 + 48.0 = 400.6 miles
• The trip falls after July 1, so the rate is $0.76: 400.6 × $0.76 = $304.46
• Tolls and parking, from the card statement in U.S. dollars: $28.31 of electronic tolls and $16.07 of client-site parking
• Total for the trip: $304.46 + $28.31 + $16.07 = $348.84

The fuel he bought in Ontario and the 25.0 personal kilometers (15.5 miles) are not in the figure. The trip was five days, and outside the United States for four days when counted under the one-week rule (September 15 to 18, not counting the day he left), so Publication 463 treats it as entirely business and no allocation of the getting-there cost is needed. That does not make the dinner drive deductible: it is personal driving, kept out of the business column and marked personal in the log.

Reconciling the odometer. The odometer shows 372.5 miles between the two border readings (41,596.5 minus 41,224.0). The maps app logged 592.5 kilometers, or 368.2 miles including the dinner drive. The 4.3-mile difference is the short moves nobody logged, such as parking-lot loops, and Marcus claims only the logged business legs.

What the kilometer mistake costs. If Marcus had typed 567.5 into a miles column and added his 48.0 U.S. miles, he would have claimed 615.5 miles × $0.76 = $467.78, which is $163.32 more than the correct $304.46. That is a record that cannot be reconciled with the odometer, exactly what an examiner looks for.

The same trip stretched to 10 days. Suppose Marcus stays on in Canada for personal time and returns Wednesday, September 23. He is outside the United States for 10 days (September 14 to 23, both the leaving and returning days counted). His last client shoot is Thursday, so Friday, September 18 follows his business activity and he stays on for personal reasons; Publication 463 says days like that are not business days. The business days are Monday (travel), Tuesday to Thursday, and the return transportation day, Wednesday, September 23, which makes 5 business days, and 5 personal days (Friday to Tuesday), or 50% of the time abroad. The trip is over a week and personal time is not under 25%, so no exception applies. Allocation then covers the cost of getting there:

• Border to Toronto and back: 138.4 km × 2 = 276.8 km ÷ 1.609344 = 172.0 miles
• 172.0 × $0.76 = $130.72
• Business share: $130.72 × 5/10 = $65.36 (and $65.36 not deductible)

His 48.0 domestic miles stay fully in, and the driving to the three clients stays business use on business days. That is the same reading flagged above, so have a CPA or EA confirm it.

Common Mistakes on Cross-Border Drives

1. Entering kilometers as miles. The result is an overstatement of about 61%.
2. Converting each leg and adding the rounded figures. Convert the total.
3. Skipping the border readings. Without them you cannot show where the domestic part of the trip ended.
4. Claiming fuel and a trip insurance policy on top of the standard rate. The rate already includes both.
5. Leaving out the toll bill that arrives later. Electronic tolls often show up weeks after the trip.
6. Using one mileage rate all year. 2026 has two. A trip before July 1 uses 72.5 cents; a trip after uses 76 cents.
7. Treating a rental car like your own. The standard rate is for a car you own or lease.
8. Dropping the personal detour from the log. Mark it personal instead, so the log shows you separated it.
9. Assuming the one-week exception covers personal driving. It affects the getting-there cost, not the miles you drove for pleasure.

How CentSense Helps

CentSense keeps the log and the receipts for a cross-border trip in one place:

• Scan toll, parking and fuel receipts with AI the day you pay, so the vendor, date and total are captured. The free tier includes 10 AI scans a month. Enter the U.S. dollar amount your card statement shows, and add the foreign amount and rate in the expense notes
• Log trips by date with a From, a To and notes on the Solo plan ($5/month). The distance field is in miles, so convert kilometers before you enter them and put the kilometer figure in the notes. CentSense's mileage export applies a single annual rate and does not apply the July 1, 2026 split (72.5 cents, then 76 cents) to each trip, so value each trip at the rate for its date
• On the Solo and Team plans, export your categorized expenses as CSV so your preparer can map them to Schedule C lines

CentSense tracks expenses and mileage. It does not decide whether a trip was entirely business, whether the one-week exception applies or how to allocate a mixed trip. Those are judgment calls for you and your CPA or EA.

Frequently Asked Questions

Can I deduct mileage when I drive my own car to Canada or Mexico for business?

Generally yes, if they are business miles you can substantiate. Publication 463 treats the drive from home to the border as ordinary U.S. travel and applies its foreign-travel limits only beyond the border. Neither the standard mileage section of Publication 463 nor Revenue Procedure 2019-46 carves out miles driven abroad, but personal driving is never deductible, and a trip over a week with 25% or more personal time can trigger an allocation. Keep a dated log and ask a CPA or EA to confirm.

How do I convert kilometers to miles for a mileage log?

Divide kilometers by 1.609344, which is the NIST factor of 1.609 344 kilometers per mile. For example, 567.5 business kilometers is 352.6 miles. Convert the total, not each rounded leg, and keep the original kilometer figure in your notes. Logging kilometers as miles would overstate the deduction by about 61%, because a kilometer is only about 0.62 of a mile. Your tax return, the IRS rate and the log elements in the regulations all work in miles, so ask a CPA or EA if your odometer reads in kilometers.

Is the drive from my home to the border treated differently from the miles abroad?

Yes. Publication 463 says travel by private car in the United States is travel between points in the United States, even on the way to a destination outside it. In its Denver to Mexico City example, the drive to the border and back is domestic and only the border-to-Mexico-City portion falls under the foreign-travel rules. If the trip is entirely business or meets an exception, you generally need no allocation. A CPA or EA can confirm which rules fit your trip.

Can I use the standard mileage rate for a rental car in another country?

Generally no. Publication 463 describes the standard mileage rate for a car you own or lease, and for a rented car it says that if you rent a car while away from home on business, you can deduct only the business-use portion of the expenses. So the rental charge and fuel are what you track, with receipts, and the country does not change that. A short-term lease could raise a closer question, so confirm your facts with a CPA or EA.

Can I deduct foreign tolls, fuel and parking when I drive abroad on business?

Tolls and parking tied to business: yes, even under the standard mileage rate. Publication 463 says that in addition to using the standard mileage rate, you can deduct business-related parking fees and tolls (but not parking at your regular place of work). Fuel is different: the standard rate already includes gasoline, so you deduct fuel only if you use actual expenses for that vehicle and year. Keep each receipt and the U.S. dollar amount from your card statement. A CPA or EA can confirm how it applies to you.

What exchange rate do I use for foreign toll and fuel receipts?

Publication 54 says you must express amounts on your U.S. tax return in U.S. dollars, translating any expenses paid in foreign currency. The IRS does not name one required rate in that passage. The practical record is the U.S. dollar amount your card statement shows for the charge, which already reflects the conversion. For cash, write the rate and its source on the receipt and use one source consistently. Foreign transaction fees are generally part of the cost. Ask a CPA or EA about unusual cases.

What if I add personal days to a business drive abroad?

Personal driving is never deductible, and personal days can also shrink the cost of getting there. If you are outside the United States a week or less, Publication 463 treats the trip as entirely business. Beyond a week, if 25% or more of your time abroad is personal, you generally allocate the getting-there cost by business days over total days. In this guide's example, a 10-day trip with 5 business days allows $65.36 of a $130.72 getting-there cost. Confirm your day count with a CPA or EA.

Authoritative References

• IRS: Publication 463, Travel, Gift, and Car Expenses
• IRS: Publication 54, Tax Guide for U.S. Citizens and Resident Aliens Abroad
• IRS: Revenue Procedure 2019-46
• IRS: Standard mileage rates (2026: 72.5 cents Jan 1 to Jun 30 per IR-2025-128; 76 cents Jul 1 to Dec 31 per IR-2026-29)
• Treas. Reg. §1.274-4, Disallowance of certain foreign travel expenses
• Treas. Reg. §1.274-5T, Substantiation requirements
• 26 U.S.C. §274, Disallowance of certain entertainment, etc., expenses
• NIST SP 811, Appendix B: Conversion factors

Stop rebuilding border crossings from memory. Start a free CentSense account, scan each toll and parking receipt with AI the day you pay, log every leg with its purpose, and export a CPA-ready breakdown at tax time. The free tier includes 10 AI receipt scans a month, and the Solo plan ($5/month) adds unlimited scans, mileage tracking and CSV export.

This guide is general education for U.S. self-employed freelancers filing a Schedule C in 2026 who drive their own car across the Canadian or Mexican border on business. It is not personalized tax advice. Whether a trip is entirely business, how the foreign-travel allocation applies to a car, whether the standard mileage rate applies to your vehicle and facts, and how to treat mixed-purpose costs depend on your circumstances, so confirm them with a CPA or EA before you file. Customs, insurance, licensing and foreign tax rules are outside this guide.