How Does the Vehicle Expense Calculator Work?

The Vehicle Expense Calculator estimates the deductible expenses associated with a business vehicle using two methods:

  • The standard mileage rate
  • The actual expense method

Its purpose is to help you make a quantitative comparison between the two methods over the expected life of a vehicle.

Without a calculator like this, it is easy to fall back on simple rules of thumb. Those rules can be useful, but they often overlook important differences in fuel costs, vehicle value, business-use percentage, depreciation, and eventual resale value.

Like any projection, this calculator is only as useful as the assumptions behind it. Those assumptions are necessarily imperfect. Below is an explanation of how the calculator works and the assumptions I have used.

The Standard Mileage Rate

The standard mileage rate is a uniform per-mile amount established by the IRS that taxpayers can use instead of calculating most of the actual costs of operating a vehicle.

The standard mileage rate is intended to account for expenses such as:

  • Depreciation
  • Fuel
  • Insurance
  • Repairs and maintenance
  • Registration
  • Vehicle washes and other miscellaneous operating costs

Certain vehicle expenses may be deductible separately because they are not included in the standard mileage rate. Since these expenses may generally be deducted regardless of whether you use the standard mileage method or actual expenses, they are excluded from this calculator.

Examples include:

  • Vehicle property taxes
  • Business tolls
  • Business parking
  • The deductible business portion of auto loan interest, when applicable

2026 Standard Mileage Rate

For 2026, the business standard mileage rate is:

  • 72.5 cents per mile from January 1 through June 30
  • 76 cents per mile beginning July 1

Because this calculator is designed primarily as a forward-looking comparison, the current rate can be entered and adjusted by the user.

Projected Increase in the Mileage Rate

Based on historical changes in the IRS standard mileage rate since 2011, the calculator assumes that the standard mileage rate will increase by approximately 2.61% per year going forward.

Obviously, the IRS does not increase the rate by a fixed percentage each year. This assumption is simply intended to provide a reasonable long-term projection.

Actual Expenses

Under the actual expense method, the calculator separately estimates fuel, electricity, insurance, repairs and maintenance, registration, and depreciation.

Only the business-use percentage of these expenses is included in the deductible amount.

Gasoline and Electricity

One reason I created this calculator is that fuel costs vary substantially by geography and by vehicle.

A driver in California uses the same federal standard mileage rate as a driver in Mississippi, even though their gasoline or electricity costs may be very different.

The calculator allows you to enter your own estimated annual fuel costs.

For future years, the calculator assumes:

  • Gasoline costs increase by 2% per year
  • Electricity costs increase by 3% per year

For a fully electric vehicle, you can enter $0 for gasoline and enter your estimated annual charging cost under electricity.

For a plug-in hybrid or other vehicle that uses both gasoline and electricity, both amounts can be entered.

Insurance

Annual insurance costs are projected to increase by 2.5% per year.

Repairs and Maintenance

Repairs and maintenance are projected to increase by 4% per year.

This assumption is somewhat higher than ordinary inflation because vehicle maintenance costs tend to be affected by two factors:

  • The increasing cost of labor and parts
  • The tendency for vehicles to require more maintenance and repairs as they age

Registration

Vehicle registration costs, excluding vehicle property taxes, are projected to increase by 2.5% per year.

Depreciation

Depreciation is by far the most difficult component of vehicle expenses to model.

There are also important differences between depreciation under the standard mileage method and depreciation under the actual expense method.

Depreciation Under the Standard Mileage Method

What many taxpayers do not realize is that part of the standard mileage rate represents depreciation.

For 2026, the depreciation component of the standard mileage rate is 35 cents per business mile.

This does not change the amount of your mileage deduction. However, it is important because the depreciation component reduces your tax basis in the business portion of the vehicle.

That can affect the amount of taxable gain or depreciation recapture when the vehicle is eventually sold.

The calculator assumes that the depreciation component of the standard mileage rate will increase by approximately 3% per year.

For example, suppose you drive 10,000 business miles in 2026 and use a 76-cent standard mileage rate.

Your mileage deduction would be:

10,000 miles × $0.76 = $7,600

Of that deduction:

10,000 miles × $0.35 = $3,500

represents depreciation for purposes of reducing the vehicle's tax basis.

Over many years, the cumulative depreciation component of the standard mileage deduction can become substantial.

Depreciation Under the Actual Expense Method

The depreciation method used for actual expenses depends in part on the percentage of business use.

Business Use of 50% or Less

If business use is 50% or less, the vehicle is generally subject to straight-line depreciation under the alternative depreciation rules.

Assuming a five-year recovery period and the half-year convention, the calculator uses:

  • Year 1: 10%
  • Years 2–5: 20% per year
  • Year 6: 10%
  • Total: 100%

Business Use Greater Than 50%

If the vehicle is used more than 50% for business, there are several possible depreciation methods.

Depending on the circumstances, a taxpayer might use:

  • Regular MACRS depreciation
  • Straight-line depreciation
  • Bonus depreciation under §168(k)
  • A §179 deduction

Trying to incorporate every possible depreciation election would make this calculator unnecessarily complicated.

I also rarely recommend maximizing accelerated vehicle depreciation without considering the consequences. Accelerating a deduction changes the timing of depreciation but does not necessarily increase the total depreciation ultimately available.

For purposes of this calculator, when business mileage exceeds non-business mileage—that is, when business use is greater than 50%—the calculator uses the standard five-year MACRS depreciation schedule.

Assuming the half-year convention:

  • Year 1: 20.00%
  • Year 2: 32.00%
  • Year 3: 19.20%
  • Year 4: 11.52%
  • Year 5: 11.52%
  • Year 6: 5.76%
  • Total: 100%

The calculator does not model bonus depreciation, §179, luxury automobile depreciation limits, or other special depreciation elections.

A Word About Depreciation Recapture

If you deduct depreciation on a vehicle—or almost any other business asset—and later sell it, some or all of the gain may have to be recognized as ordinary income because of depreciation recapture.

This is why the calculator asks you to enter an expected sale price.

If you expect to keep the vehicle until it has essentially no resale value, you can enter a very low expected sale price or $0.

Example 1: Fully Depreciated Vehicle

Suppose you purchase a vehicle for $50,000, use it 100% for business, and eventually deduct the entire $50,000 through depreciation.

Your adjusted tax basis is now $0.

If you later sell the vehicle for $10,000, the $10,000 gain is attributable to previously claimed depreciation.

Depreciation recapture = $10,000

Example 2: Partially Depreciated Vehicle

Suppose you purchase a vehicle for $50,000 and have claimed $25,000 of depreciation.

Your remaining adjusted basis is:

$50,000 − $25,000 = $25,000

If you sell the vehicle for $30,000, you have a $5,000 gain:

$30,000 − $25,000 = $5,000

Therefore, the depreciation recapture is $5,000.

If instead you sell the vehicle for $20,000, the sale price is below the adjusted basis and there is no depreciation recapture.

Example 3: Vehicle Used 50% for Business

Suppose a $50,000 vehicle is used 50% for business.

The business portion of the original basis is:

$50,000 × 50% = $25,000

Assume you have already claimed the full $25,000 of allowable depreciation on the business portion.

You then sell the entire vehicle for $20,000.

For tax purposes, the sale is effectively divided between the business and personal portions.

Business Portion

Business share of sale proceeds:

$20,000 × 50% = $10,000

Business adjusted basis:

$25,000 − $25,000 depreciation = $0

Gain attributable to the business portion:

$10,000

Therefore, the depreciation recapture is $10,000.

Personal Portion

Personal share of the sale proceeds:

$10,000

There is no depreciation recapture attributable to the personal-use portion.

The personal portion may have an economic loss, but a loss on the sale of personal-use property is generally not deductible.

Depreciation Recapture With the Standard Mileage Rate

The same general concept applies when the standard mileage rate is used.

Even though you did not separately deduct depreciation, a portion of every business mile is treated as depreciation and reduces the tax basis of the business portion of the vehicle.

Suppose a vehicle originally costs $25,000 and, over several years, the cumulative depreciation component of the standard mileage deduction becomes large enough to reduce the business basis to $0.

If the vehicle is later sold for $10,000:

  • If it was used 100% for business, as much as the full $10,000 could represent taxable gain attributable to depreciation.
  • If it was consistently used 50% for business, only $5,000 of the sale proceeds would be allocated to the business portion for purposes of calculating the business gain.

This is one reason it is important to keep accurate records of business mileage throughout the life of a vehicle.

Recordkeeping Matters

Vehicle expenses are subject to the heightened substantiation requirements of IRC §274(d).

Taxpayers should maintain adequate records of business mileage, including information such as the date, mileage, destination, and business purpose of each trip.

I have created a spreadsheet for this purpose. Download your copy here.

If you are using the actual expense method, you should also maintain records supporting vehicle expenses such as fuel, electricity, insurance, repairs, maintenance, and registration.

Good recordkeeping is important not only for calculating the current-year deduction, but also for determining the vehicle's adjusted tax basis and potential gain or depreciation recapture when it is eventually sold.

Limitations of This Calculator

This calculator is intended for educational and planning purposes only.

It relies on generalized assumptions that may not fit your individual circumstances, and its results should not be viewed as a recommendation to choose the standard mileage method or the actual expense method.

The calculator is intended to provide one useful piece of information when comparing the two approaches.

Among its limitations:

  • It does not model bonus depreciation or §179.
  • It does not incorporate the federal luxury automobile depreciation limits.
  • It does not account for state-specific depreciation differences.
  • It assumes the same annual business and personal mileage throughout the projection.
  • It assumes a constant business-use percentage.
  • It uses estimated annual rates of increase for vehicle expenses.
  • It assumes relatively smooth increases in costs even though gasoline, electricity, insurance, repairs, and other expenses can be volatile from year to year.
  • It does not attempt to predict future changes in tax law.

Most importantly, the calculator compares cumulative deductions, not actual tax savings.

A larger deduction does not necessarily produce a larger tax benefit.

For example, one method might generate larger deductions in years when your marginal tax rate is relatively low, while another method produces deductions in years when your marginal rate is higher. In that situation, the method with the larger cumulative deduction might not produce the larger cumulative tax savings.

Similarly, actual vehicle mileage and expenses inevitably vary from year to year.

Future economic conditions cannot be predicted with precision. The assumptions used in this calculator are intended to provide a reasonable and understandable simplification—not a precise forecast of what will happen.

The goal is not to produce a perfect answer. It is to provide a better framework for comparing the long-term economics of the standard mileage and actual expense methods.