HMRC mileage log requirements: what a valid business mileage record must show (with template)

HMRC does not prescribe a form, but a mileage log that stands up must show, for each business journey: the date, where it started and ended, the business purpose and the business miles, for an identified vehicle. Employers paying mileage allowances must keep records of the payments and the business journeys they relate to, for at least three years after the end of the tax year. Since 6 April 2026, the tax-free rate for employees' own cars and vans is 55p per mile for the first 10,000 business miles, then 25p.

This guide explains when a log is needed (own car, company car, pool car, sole trader), what each line must contain, the commuting and temporary workplace rules that decide which miles count, how long to keep records, a template with an example week, and the automatic alternatives to a paper log with what UK GDPR requires for each. Voltaback's box-free telematics is one of them: mileage comes from the car itself, and the employer never receives drivers' location.

Who needs to keep a mileage log, and why

A mileage log is evidence. Who needs it depends on whose car it is and what is being paid.

Two things a log does not do in the UK:

• it does not reduce a company car BIK: the benefit is based on list price and CO2, whatever the private mileage;
• it is not needed to prove that an employer's reimbursement of electricity for a company car is tax-free, if the employer reimburses all of the car's electricity: that exemption covers business and private miles alike.

The rules behind the log

Mileage allowance payments for employees' own vehicles

When employees use their own car or van for business, the employer can pay a mileage allowance up to the approved amount free of tax and without reporting it:

The rates are per employee, across all their cars, for the tax year. For National Insurance, a separate "qualifying amount" applies: 55p per business mile for cars and vans from 6 April 2026, with no drop to 25p after 10,000 miles.

HMRC's own manual is explicit about records: even when payments are within the approved amount and nothing is reported, the employer still needs to keep records of the payments made and the business journeys to which they relate.

Sources: GOV.UK, Business travel mileage: rules for tax, GOV.UK, Rules for National Insurance, HMRC EIM31240, HMRC EIM31390.

Paying more, or less, than the approved amount

• Above the approved amount: the excess is taxable. The employer reports it on form P11D or puts it through payroll.
• Below the approved amount: nothing to report, and the employee can claim Mileage Allowance Relief (MAR) on the difference, for the current tax year and the four previous ones. They need their own log of dates and business mileage to do it.
• Lump sums: a monthly car allowance is taxable salary. A lump sum only counts as a mileage allowance payment if it is calculated to cover the business share of the car's standing costs.

Sources: GOV.UK, Claim tax relief: vehicles you use for work, HMRC EIM31360.

Company cars: advisory fuel and electricity rates

For company cars, the AMAP rates do not apply. HMRC publishes advisory fuel rates each quarter, which employers can use to reimburse business travel in a company car, or to set what drivers repay for private fuel. For fully electric company cars, the Advisory Electricity Rate has been 7p per mile for home charging and 15p per mile for public charging since 1 September 2026.

If the employer pays no more than the advisory rate for business miles, there is no taxable profit and no Class 1A NIC. When a car charges both at home and in public, HMRC allows a fair and reasonable apportionment of the mileage between the two rates. That apportionment needs evidence of where the car charged, which a paper log rarely captures.

Source: GOV.UK, Advisory fuel rates.

Which miles count as business miles?

The log is only as good as the line between business and private. That line is set by the travel rules in sections 337 to 339 of ITEPA 2003.

Ordinary commuting is private

Travel between home and a permanent workplace is ordinary commuting, and never business mileage, even if the employee takes calls on the way or is on stand-by. A permanent workplace is one the employee attends regularly to perform their duties.

Travel to a temporary workplace is business

A temporary workplace is a place the employee goes to perform a task of limited duration or for a temporary purpose: a client site, a project office, a training venue. Travel from home to a temporary workplace is business mileage.

The 24-month rule

A workplace stops being temporary if the employee spends, or expects to spend, 40% or more of their working time there over a period that lasts, or is likely to last, more than 24 months. From the moment that expectation exists, the journey becomes ordinary commuting.

Common cases

Sources: HMRC EIM32065, permanent workplace, HMRC EIM32075, temporary workplace, HMRC EIM32080, the 24-month rule.

What a mileage log must contain

HMRC accepts any reasonable format, paper or digital, as long as it records the journeys behind each payment. In practice, a log that survives a compliance check has these columns:

Keep it contemporaneous: a log rebuilt at the end of the year from memory and calendars is weaker evidence than one filled in as journeys happen, and is the first thing an inspector questions.

Mileage should be the actual route driven, or a reasonable shortest route if the employer's policy says so. Either way, be consistent.

Mileage log template, with an example week

Below is a template for an employee using their own car, with a typical week. The same columns work for a company car, with the charging location column added for electric cars.

At 55p per mile, the week's approved amount is £96.25. The commutes on Monday and Wednesday are excluded, even though the car was used.

Template for an electric company car paid at the advisory rate

When the employer pays business miles in an electric company car at the Advisory Electricity Rate, the log needs one more piece of information: where the car was charged, to apportion miles between the home and public rates.

The split must be fair and reasonable. Charging receipts from public networks and the share of kWh drawn at home are the usual evidence. If the employer instead reimburses all the car's electricity at real cost, this monthly calculation disappears, and the business mileage column is only needed for internal reporting.

Worked example over a tax year

An employee drives 12,000 business miles in their own car in 2026/27.

Had the employer paid 60p per mile, the payments of £7,200 would exceed the approved amount by £1,200 (taxable, reported on P11D or payrolled) and the NIC qualifying amount by £600 (subject to Class 1 NIC).

Company cars: when does a log still matter?

A company car driver often assumes no log is needed. It depends on the energy and the policy.

Petrol, diesel and hybrid company cars

If the employer pays for fuel and the driver uses the car privately, the car fuel benefit charge applies unless the driver repays the cost of all private fuel. HMRC only accepts that if all private mileage is correctly recorded and repaid at the advisory rate or higher. Without a complete log, the fuel benefit is charged in full, which on a typical petrol car is far more expensive than the fuel itself.

Electric company cars

Electricity is not fuel for the car fuel benefit charge. The employer can reimburse the electricity used to charge a company car at home or in public, for business and private miles, with no tax and no Class 1A NIC, as long as the reimbursement is solely for the company car.

So for an electric company car, the record that matters is not business versus private miles: it is the car's charging versus the household's consumption. A business mileage log is still useful if the employer chooses to pay only business miles at the 7p or 15p advisory rate, or for cost allocation by client or project.

How the electricity reimbursement works in practice is covered in our guide to reimbursing EV charging costs, and the expense claim route in our article on EV charging expense claims.

Source: HMRC EIM23900.

Pool cars

A pool car has no benefit in kind if it is used by several employees, private use is merely incidental and it is not normally kept overnight at an employee's home. A booking sheet with driver, dates, start and end mileage and purpose is the evidence that those conditions are met.

Sole traders and partners

Self-employed people who use a vehicle for business can choose simplified expenses: a flat rate per business mile, the same 55p for the first 10,000 miles and 25p after from 2026/27, instead of actual costs. Once chosen for a vehicle, the flat rate must be kept for as long as that vehicle is used in the business, and it cannot be used for a vehicle on which capital allowances have been claimed.

Either way, the log of business miles is the basis of the claim. With actual costs, it sets the business share of running costs and capital allowances. For VAT-registered sole traders, mileage records also support VAT recovery on fuel and on electricity charged at home for business.

Sources: GOV.UK, Simplified expenses: vehicles, GOV.UK, VAT on motoring expenses (Notice 700/64).

Common mistakes HMRC finds in mileage claims

• Commuting claimed as business. The most frequent error, especially for staff who visit the office "on the way" to a client.
• The 24-month rule ignored. A long project site quietly becomes a permanent workplace once 40% of working time over more than 24 months is expected there.
• Round numbers. Weekly totals of exactly 100 or 200 miles, repeated month after month, suggest estimates rather than records.
• Logs rebuilt at year end. Calendars help, but a reconstruction made months later is weak evidence.
• Odometer totals that do not match. Business miles that exceed the car's total mileage, or private use that is implausibly low.
• Allowances above 55p with no reporting. The excess is taxable and must go on the P11D or through payroll.
• Car allowances treated as mileage payments. A flat monthly allowance is salary unless it is calculated on the business share of standing costs.
• Mixed vehicles. Business miles in a company car claimed at AMAP rates meant for own cars.

A short monthly check by the line manager (are these journeys plausible for this role?) catches most of these before they become a tax problem.

How long must mileage records be kept?

An employer that cannot produce full records can have tax estimated by HMRC and face a penalty of up to £3,000. In practice, many employers keep mileage data for six years to cover the longer limits that apply where there is carelessness, which also fits with their accounting records.

Sources: GOV.UK, PAYE: keeping records, GOV.UK, Self-employed: how long to keep your records.

Why accurate mileage matters beyond tax

A reliable mileage figure per vehicle serves more than HMRC.

• Lease bands: contract hire is priced on annual mileage. Excess mileage charges at the end of the contract are avoidable when the fleet sees the trend early.
• Maintenance: service intervals and tyre replacement follow mileage.
• Duty of care: miles driven for work are part of the risk assessment HSE expects.
• Cost allocation and emissions reporting: recharging projects or clients, and reporting business travel emissions.
• Grey fleet insurance: employees driving their own car for work need business use cover. A log showing regular business mileage is a prompt to check every driver's certificate each year, alongside their MOT.
• Car policy decisions: real business mileage per role shows who genuinely needs a company car, who is better served by a pool car, and where a car allowance costs more than it saves.

The fleet-wide view is covered in our guide to fleet mileage tracking.

How to keep a mileage log without manual entry: four methods compared

The right method depends on what you pay. If you pay AMAP on own cars, you need trip-level business mileage. If you reimburse the electricity of electric company cars, you need the car's charging data more than its trips. Many fleets need both, for different cars.

Voltaback's telematics needs no box: mileage, consumption and trips come from the car's own connection, across more than 48 brands. Trips are classified business or private in the driver app, and the employer receives the figures it needs, never the drivers' geolocation.

Mileage logs and UK GDPR: what the employer may know

A mileage log linked to a named employee is personal data. A log built from location tracking is more intrusive still. The Information Commissioner's Office (ICO) guidance on monitoring workers sets the expectations:

• a clear purpose, such as paying mileage correctly, and no collection beyond it;
• transparency: drivers know what is collected, why, who sees it and for how long;
• a data protection impact assessment where monitoring is likely to be high risk, which continuous vehicle tracking often is;
• respect for private time: tracking a car used privately outside working hours is hard to justify, and drivers should be able to switch it off where business use does not require it.

A log that records business trips with postcodes is proportionate for AMAP. A minute-by-minute location history of every evening and weekend is not needed to pay mileage. The detailed rules are in our guide to vehicle tracking for company cars.

Source: ICO, Employment practices and data protection: monitoring workers.

Setting up a reliable mileage record in four steps

1. Decide what each team needs

Payroll needs business miles per employee and month. Finance needs totals by cost centre. The fleet manager needs odometer readings per vehicle. Write these down before choosing a tool, so you collect once.

2. Set one cut-off date

Align the mileage period with the payroll month. A single cut-off avoids the classic gap between the last log and the payment run.

3. Remove manual entry where you can

For connected cars and drivers who agree, take mileage from the car. Keep the paper or spreadsheet route only for the vehicles that cannot connect, and check them against odometer readings.

4. Send the data where it is used

A monthly export for payroll, a per-vehicle history for the fleet tool, and an archive that meets the retention periods above.

Get the mileage without the weekly chore

A valid HMRC mileage log is simple on paper: date, route, purpose, miles, vehicle. The hard part is getting drivers to fill it in every week, and keeping location data proportionate when the log is automated.

Voltaback reads mileage and trips directly from the car, with no box to fit, and lets drivers classify business and private trips. The employer gets the figures for payroll, never the drivers' geolocation, with ISO 27001 certification since 2 December 2025 and UK GDPR compliance. More than 200 companies already use Voltaback for their fleet.

See how it works on our box-free telematics page, or talk to us about your fleet's mileage.