Business Mileage Calculator
Estimate the approved mileage amount for an employee using their own vehicle on qualifying business journeys.
LedgerKit provides estimates based on the information entered and the configured rates. Results do not constitute accounting, tax or legal advice. Check the latest official guidance or consult a qualified professional before acting on a calculation.
How this calculator works
Select the tax year and vehicle, then enter previous business miles and the new miles. For cars and vans, new miles are split across the 10,000-mile threshold when needed.
This is an approved mileage amount, not a vehicle’s actual running cost. Employer mileage reimbursement reduces the shortfall. An optional marginal tax rate estimates a reduction in tax, not a reimbursement of the shortfall.
Worked example
In 2026/27, 9,500 previous car miles and 1,000 new miles gives 500 × £0.55 + 500 × £0.25 = £400. In 2025/26, the first-band rate is £0.45.
Frequently asked questions
Does ordinary commuting qualify?
Ordinary travel between home and a permanent workplace generally does not. Business travel and temporary-workplace rules can be complex; check the official guidance.
Is the mileage shortfall my tax refund?
No. It is the eligible amount potentially available for Mileage Allowance Relief. Any tax saving depends on your tax position and is generally a fraction of the shortfall.
How are passengers treated?
The separate passenger amount applies to qualifying fellow employees on the same business journey in your car or van. There is no tax-relief estimate on an unpaid passenger-payment shortfall.
Can I use this for a company car or self-employed expenses?
This tool is for employee-owned vehicles. Company cars use different rules. Self-employed simplified expenses have separate eligibility rules and should be checked independently.