How to calculate real expenses for French taxes: complete method

What are real expenses for French taxes?

When you declare French employment income, the tax authority automatically applies a 10% standard deduction to account for common professional expenses. You do not need to calculate anything to benefit from it.

But if your actual work-related expenses are higher than this automatic deduction, you may choose the real expenses option instead. In that case, you replace the 10% deduction with the total amount of justified professional expenses: home-to-work commuting, mileage expenses, meals in certain cases, tolls, parking, equipment or other expenses required for your work.

This option can be useful, but it requires more care. You must be able to explain your calculation and support the amounts if the French tax authority asks for details.

Key point: real expenses are not an automatic tax reduction. They are a filing option that may be worthwhile only if your justified professional expenses exceed the 10% standard deduction.

Real expenses or the 10% deduction: the basic comparison

The choice is based on two amounts:

1. the automatic 10% deduction;
2. the total amount of your justified professional real expenses.

If your real expenses are higher, the option may be interesting. If they are lower, the automatic deduction is usually simpler and more favorable.

Be careful: when choosing real expenses, certain reimbursements or allowances paid by your employer may need to be added back to your taxable income. That is why you should not only look at the gross amount of expenses. You need to consider your full situation.

Before calculating: information to prepare

Before you calculate, prepare the following information:

• your taxable employment income or the income used to compare with the 10% deduction;
• your actual working days;
• your number of home-to-work commute days;
• your telework days;
• the one-way distance between your home and workplace;
• the type of vehicle used, if you calculate mileage expenses;
• tolls, parking or work-related stationing costs;
• meal expenses that may be deductible;
• employer reimbursements, meal vouchers or employer contributions already received;
• available supporting documents.

The earlier you prepare this information, the less you will need to reconstruct your year roughly when filing.

Step 1: count the days that actually matter

This is the most important step. Many mistakes come from counting days incorrectly.

You should not simply start from 365 days and subtract a few absences. For commute expenses, what mostly matters is the number of days when you actually travelled between home and work.

You should separate:

• working days;
• on-site working days;
• telework days;
• paid leave;
• RTT days;
• sick leave;
• non-worked public holidays;
• other absences.

Simple example:

Working days during the year: 210
Telework days: 80
Home-to-work commute days: 130

In this example, home-to-work mileage expenses should be calculated on 130 commute days, not on 210 working days. Telework is still work, but it does not generate a home-to-work commute.

This is exactly the kind of distinction that the Outilo real expenses calculator helps clarify.

Step 2: calculate transportation expenses

Transportation expenses are often the largest real expense category. They may include:

• use of a car;
• use of a motorcycle or two-wheeler;
• public transportation;
• tolls;
• workplace parking or stationing costs.

If you use a personal vehicle, you can usually estimate expenses using the mileage scale published by the French tax authority or, in some cases, using actual expenses. The scale depends notably on the vehicle type, its fiscal horsepower and the number of professional kilometers driven.

The basic reasoning is simple:

Round-trip distance × number of commute days = annual professional kilometers

Then this mileage is valued using the method applicable to your vehicle and tax year.

Step 3: understand the 40 km rule

For home-to-work commuting, the distance is generally taken into account within a limit.

If your home is located 40 km or less from your workplace, you can generally include the full round-trip mileage.

If your home is located more than 40 km from your workplace, the calculation is normally limited to the first 40 km. The full distance may be accepted only if you can justify the distance by specific circumstances: job-related reasons, family situation, social constraints, professional mobility, difficulty finding a job closer to home, and so on.

In that case, prepare an explanatory note and keep documents supporting your situation.

Important point: unless there is a specific constraint, you can generally count only one home-to-work round trip per day.

Step 4: know what the mileage scale already includes

If you use the mileage scale, you should not add a second time expenses already covered by that scale.

The scale takes into account vehicle-related costs such as:

• vehicle depreciation;
• repairs and maintenance;
• tyres;
• fuel;
• insurance.

However, some expenses may be added separately when they are work-related and justified, including:

• tolls;
• certain parking or stationing costs;
• certain garage costs;
• in some cases, interest related to a vehicle loan, in proportion to professional use.

The rule to remember: no double deduction. If an expense is already covered by the mileage scale, do not add it again separately.

Step 5: handle meal expenses carefully

Meal expenses may be included in real expenses, but not automatically.

The idea is not to deduct all your meals. Deductible meal expenses correspond to the additional costs incurred because your work requires you to eat away from home.

The calculation depends on your real situation:

• can you go home for lunch?
• do you have access to a company canteen or collective catering?
• have you kept receipts?
• do you receive meal vouchers?
• does your employer fund part of the meal?

If your employer contributes to the meal, that contribution must be taken into account. If you receive meal vouchers, the employer-funded part must also be deducted from the amount retained.

For this reason, avoid quick calculations such as “one fixed amount per meal” without checking your actual situation.

Step 6: compare with the 10% deduction

Once your expenses are estimated, compare them with the automatic 10% deduction.

You can reason like this:

Automatic deduction ≈ relevant income × 10%
Total real expenses = transport + meals + other justified professional expenses

If total real expenses are higher than the deduction, the real expenses option may be useful. If total expenses are lower, it is usually better to keep the automatic deduction.

But do not stop at the first result. Also check:

• employer reimbursements that may need to be added back;
• expenses that are not sufficiently supported;
• amounts already covered by a scale;
• personal expenses that are not deductible.

Simple example of the reasoning

Imagine a person who works partly on site and partly from home.

They first count real commute days:

Working days: 215
Telework days: 70
Days without commute due to leave, sickness or absence: already excluded
Home-to-work commute days: 145

Then they calculate professional mileage:

One-way distance: 22 km
Round-trip distance: 44 km
Commute days: 145
Annual home-to-work mileage: 44 × 145 = 6,380 km

They can then value this mileage using the applicable method, add justified costs such as tolls or parking, then compare the total with the 10% deduction.

This example is intentionally simple. The goal is not to replace a full tax return, but to avoid major calculation mistakes.

Which supporting documents should you keep?

You do not need to attach every document to your tax return, but you must be able to provide them if the tax authority asks.

Keep in particular:

• work schedules or attendance calendars;
• records of telework days;
• paid leave, RTT or absence records if useful;
• vehicle registration or documents related to the vehicle used;
• toll receipts;
• parking or stationing invoices;
• meal receipts;
• invoices for professional equipment or supplies;
• an explanatory note if your commute exceeds 40 km;
• information about employer reimbursements.

Good habit: archive your calculation, assumptions and supporting documents in the same folder. If you need to explain the amount later, you will save a lot of time.

Calculate automatically with the Outilo calculator

You can do the calculation manually, but it is easy to make mistakes with days, commutes and the comparison with the 10% deduction.

The Outilo real expenses calculator helps you:

• count actual working days;
• separate commute days from telework days;
• estimate home-to-work mileage;
• add certain additional expenses;
• compare with the automatic 10% deduction;
• copy a summary to keep a record of your calculation.

The tool does not replace official tax rules, but it helps you build a cleaner estimate before filing.

Key takeaways

Real expenses may be useful if your justified professional expenses exceed the automatic 10% deduction. But they require a clean method.

The essentials:

• do not confuse working days with commute days;
• do not count telework days as commute days;
• check the 40 km rule;
• do not add twice expenses already covered by the mileage scale;
• handle meal expenses carefully;
• keep supporting documents;
• always compare with the 10% deduction before choosing.

If your situation is complex or the amounts are significant, check the official rules or seek professional advice.