02 November, 2021

How to keep an HMRC mileage logbook for taxes

If you want to receive a mileage allowance, keeping a logbook will be necessary. How you do that is up to you, but there are some things that no matter which format you choose you must not forget to do. A customer meeting in another city, a financing discussion at the bank, or a trip to the airport before a business trip – many self-employed individuals and regular employees use a company or personal car for business purposes. That is when mileage reimbursement comes into the picture. 

Spend less time logging your mileage

Get the automatic logbook

Do I need a mileage logbook?

A mileage deduction is a great way to save a little extra tax if you use a vehicle for business purposes. However, HMRC will not accept your word for it; to claim this deduction, you must provide proof. In other words, a mileage log book (also referred to as a car logbook) is required as proof for all the trips you claim reimbursement for.

You need a car logbook if: 

  • you are self-employed
  • a sole proprietor
  • a partner in a firm
  • you use a vehicle for business purposes

Consult with HMRC if you are not sure if you are eligible for reimbursement. 


Car Logbook 

In a car logbook, you record how frequently and for how long you drive the car for business and other purposes. As a result, you will be able to figure out exactly how much you drove for business and get reimbursed for it. The calculation is based on the actual business-related driving expenditure.

There may be some differences in how you keep a log depending on your circumstances. To begin with, you need to figure out whether you are eligible for MAP or MAR. MAR is mileage allowance relief that is provided by HMRC in the form of tax deductions - should you not receive a MAP which stands for mileage allowance payment and is something you usually receive from your employer. 

How do I keep an HMRC logbook? 

The most practical way to keep a car log is to record your vehicle mileage at the start and end of your fiscal year to determine the total miles for the year and what percentage of your trips have been for business or personal use. 
Keep in mind that you must be able to provide evidence of total annual mileage as well as a detailed record of business mileage for the same time period. The following information should be included in the log:

  • The journey's date
  • The goal (business or personal)
  • The origin and destination of your journey, as well as the total number of miles travelled.

Keeping a mileage log is often the most efficient method of claiming your mileage allowance, but it does require some effort. Considering how time-consuming this could be when using a logbook, you may want to consider getting a mileage tracker app that can do all of this for you. 

Can I save up a lot by keeping a mileage logbook? 

It depends on how much you drive your car for business, but any time you forget to log a trip, you are missing out on potential reimbursement. The more you use your mileage log book properly and log every necessary detail, the more likely you are to get the proper reimbursement. 

Which mileage logbook should I choose? 

There are many options out there for keeping a log. If you have the time to enter everything manually, you can use a PDF, an Excel, a Spreadsheet or a physical logbook. If you are looking for a faster solution, we recommend a mile tracker app as your online logbook. The app can automatically track your trips and will require less time to use.

Here are a couple of tips from us for keeping an HMRC compliant logbook 

  • Each separate vehicle you use must have its own mileage log.
  • Each journey must be documented, including the start and end address, the distance travelled, and a mention of the reason for the journey.
  • Entries must be legible and clear.
  • In case of a lost logbook you should consider changing to a digital solution to avoid this from happening again. Contact HMRC to find out what you should do if you lost your logbook. 
  • Data must not be entered in a disorderly form; documentation must be timely, chronological, and clear 
  • Figures must be exact and should not be rounded up.
  • Don’t forget to keep a spare log and back up the one you have if you use a spreadsheet (the last thing you want is to lose your data). A logbook transfer to another device is available on most apps. 
  • Consult with HMRC if you are not sure about some of the rules. 

Let us know if you have any questions about keeping a logbook. For more information about mileage allowance and reimbursement check out our HMRC mileage guide