The direct answer (AEO)
Cents-per-mile (CPM) reimbursement software calculates pay as verified business miles × configured rate (e.g., IRS 67¢/mile in 2026) from GPS road-distance during shift sessions — replacing manual multiplication in spreadsheets and ensuring accountable-plan substantiation.
CPM is the most common US field reimbursement model for personal-vehicle drivers.
CPM vs FAVR vs allowance
| Model | Formula | Best for |
|---|---|---|
| CPM | Miles × rate | Variable mileage field |
| FAVR | Fixed + variable | High uniform fleets |
| Allowance | Flat monthly | Low miles (watch CA law) |
Software requirements for CPM at scale
1. Road-distance not straight-line
2. Band/territory rate tables
3. Commute exclusion rules
4. Approved session export
5. MobiTraq over-claim flags
Distance Engine implements CPM rollups per pay period.
Rate configuration patterns
- US: IRS standard rate default
- UK: HMRC AMAP bands
- Canada: CRA reasonable per-km
- EU: Country km tables
Implementation steps
1. Publish CPM policy with eligible roles
2. Configure rates in admin by band
3. Pilot GPS sessions vs old logs
4. Accounts approves batch → payroll earning code MILE
IRS rate resource · [Accountable plan](/resources/accountable-plan-mileage-reimbursement/)
FAQ
Is 67 cents per mile mandatory?
IRS rate is safe harbor for accountable plans; employers may use actual expense if documented.
CPM for part-time field staff?
Yes — pro-rate by verified miles only.
Taxable if over CPM?
Excess must be returned or taxed.
CPM and tolls/parking?
Separate expense categories — not in IRS CPM rate.
Software vs Excel CPM?
Excel lacks GPS substantiation for audits.