A mileage or expense log is a record, not an automatic tax claim. Its job is to keep the date, purpose, journey or cost, supporting evidence and review decision together. The tax treatment can differ between a sole trader, partnership, company and employee.
Keep the method clear
For a Mileage entry, enter the business miles and the £/mile rate. For an Expense entry, enter the actual expense amount in GBP; do not treat it as a mileage rate. The workbook calculates mileage as miles × £/mile and an expense as the actual amount entered.
Avoid duplicate vehicle costs
Do not claim actual vehicle costs for the same vehicle costs covered by the mileage method you have selected. Review the business and personal-use position, evidence and applicable method before a figure is used in accounts, payroll or a tax return.
Record the business reason
For mileage, record the date, start and end location, business reason and distance. For an expense, record the supplier, type of cost, amount, payment method and evidence location. Do not record a home-to-normal-workplace commute as though it were business travel.
Related FoxSums resources
- Business Expenses for Sole Traders: What to Check Before Claiming
- Bookkeeping for Small Businesses: Why It Matters
- Monthly Finance Checklist for Small Businesses
Next step
Record the business purpose and evidence when the journey or cost happens, not at year end.
Important
General information only. Check the facts and current official guidance for the business’s circumstances.
Sources and review
- Evidence check date: 3 November 2026.
- GOV.UK - Travel costs if you are self-employed
- GOV.UK - Expenses if you are self-employed