mBurse Blog

Why the IRS Mileage Rate Can Overpay or Underpay Workers

Written by Ian Roberts | Jun 6, 2026, 12:00:00 PM

Many employers use the IRS business mileage rate because it is familiar, simple, and easy to apply. However, the IRS mileage rate is a national benchmark. It may not accurately reimburse every employee who uses a personal vehicle for work.

The rate can overpay some high-mileage drivers, underpay some low-mileage drivers, and miss important differences in location, vehicle costs, insurance, depreciation, fuel, maintenance, taxes, and registration.

Quick Answer: Why Can the IRS Mileage Rate Incorrectly Reimburse Workers?

The IRS mileage rate can incorrectly reimburse workers because it applies one national cents-per-mile rate to employees with different mileage levels, vehicle costs, territories, and locations.

A single mileage rate may overpay high-mileage employees whose fixed costs are spread across many miles and underpay low-mileage employees who still have insurance, depreciation, registration, taxes, and other fixed vehicle costs. Employers should review whether the IRS mileage rate fits their workforce or whether a more customized reimbursement method is needed.

What Is the 2026 IRS Business Mileage Rate?

For 2026, the IRS business mileage rate is:

  • 72.5 cents per mile for business miles driven January 1 through June 30, 2026
  • 76 cents per mile for business miles driven July 1 through December 31, 2026

These rates are useful benchmarks, but they are not automatically the best reimbursement method for every workforce. Employers should review whether one national rate accurately reflects employee mileage levels, locations, fixed costs, and variable operating costs.

Should Employers Use the IRS Mileage Rate for Reimbursements?

The IRS mileage rate may work well when employees drive similar mileage levels, work in similar cost regions, and have vehicle costs close to national assumptions.

It may work less well when employees cover different territories, drive very different mileage levels, or face different fuel, insurance, maintenance, depreciation, registration, tax, and repair costs.

Employers should compare the IRS rate against actual workforce mileage, employee location, vehicle-cost assumptions, and state reimbursement requirements before deciding whether it is the right method.

How Is the IRS Mileage Rate Calculated?

The IRS standard mileage rate is based on national vehicle-cost assumptions. It is designed to provide a simplified cents-per-mile amount for business use, but it does not personalize reimbursement for each employee’s territory, mileage level, or vehicle-cost profile.

That simplicity is helpful, but it can also create reimbursement gaps. Employees in different regions may face different fuel, insurance, maintenance, repair, registration, tax, and depreciation costs. Employees also drive different numbers of business miles, which affects how fixed costs are recovered.

How Reliable Is the IRS Mileage Rate for Employee Reimbursement?

The IRS mileage rate is reliable as a national benchmark, but it is less reliable as a personalized employee reimbursement method. It does not adjust for each employee’s location, mileage level, vehicle type, territory size, or fixed-cost profile.

Even when the IRS updates the rate, a national cents-per-mile amount may still overpay some employees and underpay others. Low-mileage drivers may struggle to recover the business-use portion of fixed costs, while high-mileage drivers may receive more than needed for those same fixed costs.

3 Reasons One Mileage Rate Can Miss the Mark

1. Location affects vehicle costs

Fuel, insurance, registration, taxes, maintenance, and repair costs can vary significantly by region. A national mileage rate may be too high for some employees and too low for others.

2. Mileage level affects cost per mile

Fixed costs such as insurance, depreciation, registration, taxes, and license fees exist even when employees drive fewer business miles. Low-mileage drivers may not receive enough mileage reimbursement to cover the business-use portion of those fixed costs, while high-mileage drivers may receive more than needed for fixed costs.

3. Vehicle costs change over time

Fuel, insurance, maintenance, and repair costs can change throughout the year. A standard mileage rate is simple, but it may not adjust quickly enough to reflect every employee’s actual experience.

Where the IRS Mileage Rate Can Create Reimbursement Gaps

The IRS mileage rate is simple, but one national rate may not fit every driver, territory, or vehicle-cost profile.

Gap area What happens Who may be affected Employer fix
Mileage Low-mileage underpayment Fixed costs may not be fully recovered when reimbursement is based only on miles driven. Employees with smaller territories or fewer business miles. Review fixed costs separately from mileage-based costs.
Mileage High-mileage overpayment Fixed costs are spread across many miles, so one cents-per-mile rate may pay more than needed. Employees with large territories or high business mileage. Compare reimbursement by mileage band and territory.
Location Regional cost differences Fuel, insurance, registration, taxes, maintenance, and repair costs vary by location. Employees in higher-cost or lower-cost markets. Use localized vehicle-cost data instead of one national assumption.
Timing Changing vehicle costs Fuel, insurance, maintenance, and repair costs can change during the year. Employees whose vehicle expenses rise faster than the benchmark rate changes. Review reimbursement assumptions regularly.
Method One-rate simplicity The same rate is applied to every driver regardless of mileage, location, or cost profile. Mobile workforces with different roles, territories, or driving patterns. Evaluate FAVR or another cost-based reimbursement method.

What Is a Better Alternative to the IRS Mileage Rate?

The best alternative depends on the workforce. Some employers may use a company-set mileage rate, actual expense reimbursement, or a structured accountable reimbursement method.

For employers with frequent drivers, multiple territories, or different mileage levels, FAVR may be a better fit. FAVR, or Fixed and Variable Rate reimbursement, separates fixed vehicle costs from variable operating costs. It uses a standard vehicle, localized cost data, and documented business mileage to calculate reimbursement.

FAVR can generally support tax-free reimbursement when IRS requirements are met and business mileage is properly documented. However, it requires more structure than a simple cents-per-mile rate, including mileage tracking, policy administration, and reimbursement calculations.

Using FAVR to Address IRS Mileage Rate Gaps

FAVR, or Fixed and Variable Rate reimbursement, can help address gaps created by one national mileage rate because it separates fixed vehicle costs from variable operating costs.

Instead of standardizing only the reimbursement rate, FAVR uses a standard vehicle, localized cost data, and documented business mileage to calculate reimbursement. This can help low-mileage drivers recover fixed costs more accurately while reducing the risk of overpaying high-mileage drivers.

FAVR can generally support tax-free reimbursement when IRS requirements are met, business mileage is substantiated, and accountable-plan rules are satisfied. It requires more structure than a basic mileage rate, including mileage tracking, employee eligibility review, reimbursement calculations, and ongoing administration.

FAQs About the IRS Mileage Rate and Employee Reimbursement

Why can the IRS mileage rate incorrectly reimburse workers?

The IRS mileage rate can incorrectly reimburse workers because it applies one national rate to employees with different mileage levels, vehicle costs, locations, and territories.

Does the IRS mileage rate overpay some employees?

It can. High-mileage employees may receive more than needed for fixed vehicle costs because those costs are spread across many business miles.

Does the IRS mileage rate underpay some employees?

It can. Low-mileage employees may not receive enough reimbursement to cover the business-use portion of fixed costs such as insurance, depreciation, registration, taxes, and license fees.

What is the 2026 IRS business mileage rate?

For 2026, the IRS business mileage rate is 72.5 cents per mile for business miles driven January 1 through June 30 and 76 cents per mile for business miles driven July 1 through December 31.

Is the IRS mileage rate required for employee reimbursement?

No. The IRS mileage rate is a benchmark. Employers may choose another reasonable reimbursement method, but they should review tax treatment, substantiation, state reimbursement rules, and employee fairness.

Is FAVR better than the IRS mileage rate?

FAVR may be better for employers with frequent drivers, multiple territories, or different mileage levels. It separates fixed and variable vehicle costs and can generally support tax-free reimbursement when IRS requirements are met.

Not sure whether the IRS mileage rate is accurately reimbursing your employees? mBurse can help you compare your current mileage reimbursement method against employee mileage, localized vehicle costs, fixed expenses, variable costs, and FAVR options.