Mileage Log for the Self-Employed: When Is It Required and How to Keep One

A mileage log is one of the most dreaded administrative tools for Czech self-employed individuals. Few people enjoy keeping one, but for many OSVČ it's a legal requirement. Without a properly maintained mileage log, you can't prove your actual vehicle operating expenses — and the tax authority can disallow those expenses. In the worst case, you could face a fine of up to 500,000 Kč.

On the other hand — if you keep your mileage log correctly and consistently, you have a powerful tool for tax optimization in your hands. Actual vehicle expenses can be significantly higher than the flat-rate transport deduction of 5,000 Kč per month, and your mileage log is precisely the evidence that backs those expenses up.

In this article, we'll cover when a mileage log is required, what it must contain, how to keep one simply and without stress, and what mistakes to watch out for. We draw on the currently applicable Act No. 586/1992 Coll., on Income Taxes and the methodological guidelines of the Czech Financial Administration.

When Is a Mileage Log Required

A mileage log is not a universal obligation. The Income Tax Act doesn't explicitly require it as a standalone document. However, keeping one follows from the general obligation to substantiate tax deductions — and when it comes to vehicle operating expenses, a mileage log is practically the only acceptable way to do that.

When You Don't Need to Keep a Mileage Log

There are situations where you can avoid keeping a mileage log entirely:

What a Mileage Log Must Contain

The law doesn't prescribe an exact mileage log format, but the requirements of the Financial Administration and case law make it clear what each entry should include.

Required Information for Each Trip

Recommended Additional Information

Beyond the required minimum, we also recommend recording:

• Departure and arrival time — especially for longer trips or when billing time to a client
• Fuel top-ups — date, location, number of litres, and price (linked to receipts)
• Driver's name — if the vehicle is used by more than one person (employees, collaborators)

Mileage Log Template

Let's look at what a properly kept mileage log looks like in practice.

How to Keep a Mileage Log: Electronically vs. on Paper

The law doesn't prescribe the format for keeping a mileage log. You can choose whatever method works best for you.

Paper Mileage Log

Pre-printed mileage log booklets are available at stationery shops or print shops. They include columns for all the required information.

Advantages:

• Simple, no technology needed
• Always at hand in the car
• Straightforward for the tax authority

Disadvantages:

• Manual calculation of totals
• Prone to damage
• Corrections are difficult (corrections look suspicious)
• Difficult to back up

Electronic Mileage Log in a Spreadsheet

A simple solution is to keep your mileage log in Excel or Google Sheets. Set up a template with the required columns and monthly tabs.

Advantages:

• Automatic totals and averages
• Easy filtering and searching
• Cloud backup available
• Clear monthly and annual summaries

Disadvantages:

• You have to transfer entries from the car to your computer
• During a tax authority audit, authenticity may be questioned (we recommend regular PDF exports)

GPS Apps and Tracking Devices

The most modern option is GPS trackers or mobile apps that automatically record your route, distance, and trip time.

Advantages:

• Automatic route and kilometre tracking
• Minimal manual effort
• Accurate data (GPS coordinates)
• Difficult for the tax authority to dispute

Disadvantages:

• You still need to add the trip purpose manually
• Monthly costs (app subscription or device purchase)
• Dependent on GPS signal and phone battery

How to Correctly Classify Business vs. Personal Trips

Distinguishing business trips from personal ones is crucial, because only business kilometres can be claimed as a tax deduction. The definition is straightforward, but in practice borderline situations arise.

Clearly Business Trips

• Travelling to a client for a meeting, to hand over a project, or for a consultation
• Travelling to a construction site, client's premises, or client's workplace
• Delivering goods or materials
• Attending training or a conference related to your business
• Travelling to a government office (tax authority, trade licensing office, social security administration)
• Travelling to the post office with a business parcel
• Travelling to the bank for your business account

Clearly Personal Trips

• Dropping children off at school
• Grocery shopping for the household
• Travelling on holiday
• Visiting a doctor (unless related to a workplace injury)
• Visiting relatives

Borderline Cases

Home to Office: Business or Personal Trip?

This is one of the most frequently asked questions and a common source of disputes with the tax authority.

The basic rule: Travelling from your home to your regular place of work (office, premises) is treated as a personal trip — by analogy with employees, who are not reimbursed for commuting either.

Exceptions:

• If your office is at home (you work from home) and you travel directly to a client, it's a business trip
• If you visit multiple clients in one day without returning to your office in between, the entire route is a business trip
• If you're transporting materials or tools from home to a job site, it's a business trip

The Most Common Mileage Log Mistakes

The tax authority scrutinises mileage logs carefully during audits. Here are the mistakes inspectors catch most often — ones that can end up costing you dearly.

1. Filling Everything in at Once, Retrospectively

The most common and riskiest mistake. A sole trader ignores the mileage log all year, then "writes it up" at the end of the year (or just before an audit). An inspector will spot this by:

• The same handwriting and pen colour throughout all entries
• Numbers that are suspiciously round (always exactly 50 km, 100 km)
• Logical inconsistencies (a trip on a day you were provably somewhere else)
• No personal trips recorded (nobody drives 100% for business)

2. Zero Personal Trips

If there isn't a single personal trip in the mileage log, it's a red flag for the tax authority. Even if you use your car primarily for business, you occasionally stop at a shop or drop someone off. A reasonable share of personal trips (10–30%) paradoxically makes your records more credible.

3. Vague or Imprecise Trip Purposes

An entry saying "business trip" or "work" isn't enough. The tax authority expects a specific purpose: who, where, and why. Correct example: "Meeting with client Novák s.r.o., Brno, Masarykova 10 — delivery of price quote."

4. Mismatch with the Odometer

If the total kilometres in your mileage log don't tally with the odometer reading, that's a problem. The tax authority can request the report from your vehicle's roadworthiness inspection (which records the odometer reading) and compare it with your records.

5. Unrealistic Routes and Distances

An inspector can verify distances on a map. If you record that the Prague–Brno journey was 150 km (actually around 210 km), or conversely that a short city trip was 50 km, that raises suspicion.

6. Business Trips on Weekends and Public Holidays Without Justification

Business trips on weekends and public holidays are perfectly legitimate, but you need to be able to explain them (emergency repair at a client's site, attending a trade fair, etc.). Regular Saturday "business trips" with no specific reason will be challenged.

Penalties for Not Keeping a Mileage Log or Keeping One Incorrectly

Practical Tips for Keeping a Consistent Mileage Log

Mileage Log and Employees

If you're self-employed and have employees who use a company vehicle, additional obligations apply:

• The employee must keep a mileage log for the company vehicle they use
• If an employee also uses the company car for personal purposes, 1% of the vehicle's acquisition price must be taxed as a non-monetary benefit for the employee (monthly)
• An employee on a business trip using their own vehicle is entitled to travel allowances (basic allowance + fuel) — in that case, they must keep a mileage log to calculate the reimbursement

Frequently Asked Questions (FAQ)

Can I keep a mileage log in a mobile app?

Yes, mobile apps are fully accepted. The important thing is that the app records all required information and allows you to export data for a potential tax authority audit. We recommend regular PDF exports as a backup.

How precisely do I need to record the route?

The route should be specific enough for an inspector to verify it. You don't need to list every street, but include the starting point, destination, and any major stops. Example: "Prague, office → D1 motorway → Brno, Hybešova 34 → D1 motorway → Prague, office."

What if I forgot to record a few trips?

Add them as soon as possible, while you still remember the details. If you're keeping a paper log, retrospective additions are visible (different ink, different handwriting). With electronic records, this isn't an issue. It's always better to add an entry — even with slightly less precision — than to leave it out entirely.

Do I need to record personal trips too?

We recommend it, even though you don't need to go into detail for personal trips. The date, kilometres, and a note saying "personal" is enough. The combined total of business and personal km must match the odometer reading.

How do I handle a mileage log when multiple drivers use the same car?

If one vehicle is used by more than one person (you and an employee, you and a collaborator), each driver should record their own trips in the mileage log. We recommend adding the driver's name to each entry.

Can the tax authority tell if I've been filling in the mileage log retrospectively?

Yes, and fairly easily. An inspector can request GPS data from your mobile phone, records from motorway toll systems, compare entries with invoices (meeting location vs. route in the mileage log), or cross-check odometer readings from roadworthiness inspection reports. A fabricated mileage log is a serious problem that can lead to charges of tax fraud.

Does the mileage log requirement apply to motorcycles too?

Yes — if you claim actual operating expenses for a motorcycle, you must keep a mileage log in exactly the same way as for a car.

Useful Links to Official Sources

• Czech Financial Administration – Personal Income Tax — tax obligations for the self-employed
• Act No. 586/1992 Coll., on Income Taxes — § 24 para. 2 (tax-deductible vehicle operating expenses)
• Act No. 235/2004 Coll., on VAT — obligations for VAT payers claiming deductions
• Travel Allowance Regulations for 2026 — basic allowance rates and average fuel prices
• Moje daně Portal — electronic tax return submission

---

Disclaimer: This article is for informational purposes only and does not substitute professional tax advice. The information reflects legislation in force as of February 2026. For guidance on your specific situation, we recommend consulting a tax adviser or your local tax authority.