How to calculate real expenses for taxes: complete 2026 guide

Working days are the basis of the calculation

Start with 365 days and subtract vacation, public holidays, sick leave, and rest days. This base determines whether real expenses are worth it.

Real expenses must be justified

Unlike the 10% deduction, you must keep your receipts and supporting documents. The tax authorities can request them up to 3 years later.

Compare before choosing

Real expenses are not always more advantageous. Calculate both options (real expenses vs 10% deduction) to see which one actually saves you money.

Mileage is often the biggest expense

If you use your car to get to work, it's usually your largest deductible expense. Use the official 2026 rate (€0.636 per km for a 5 CV car up to 5,000 km).

Why real expenses change your tax return

Every year, you must choose between two options when declaring your professional income: the standard 10% deduction or the deduction of real expenses. This second option can save you several hundred euros, but only if you calculate it correctly.

The problem? Many employees don't know where to start. They forget expenses, miscalculate their working days, or don't know if this option is really worth it. Result: they leave money on the table.

What you need to know before you start

Real expenses are all the professional expenses you incurred to work: transportation, meals, work clothes, supplies, etc. Unlike the 10% deduction, you must justify each expense and declare them precisely.

Important: you cannot combine both options. You must choose one or the other for the entire tax year. Once you've opted for real expenses, you must justify them to the tax authorities if they ask.

Information to gather

Before calculating, gather this data:

Your number of days actually worked in the year (365 days minus vacation, public holidays, sick leave, etc.)
Your annual professional mileage (if you use your car)
Your public transportation costs
Your meals taken outside your home
Your work-specific clothing
Your professional supplies
Your training or documentation costs

Tip: note the information as you go through the year. It's much easier than reconstructing everything in April.

How to calculate your actual working days

This is the most important step, as it determines the basis of your calculation. Here's the method:

Start with 365 days, then subtract:

Paid vacation: usually 25 days (or more depending on your contract)
Public holidays: approximately 11 days in France in 2026
Sick days: days when you didn't work
Rest days: if you work less than 5 days per week
Remote work days: they count as working days, but you must note them separately for associated expenses

Concrete example: You're a standard employee (5 days/week), you took 25 days of vacation, there are 11 public holidays, and you had 3 sick days.

365 days - 25 vacation - 11 holidays - 3 sick = 326 working days

But be careful: if you work only 4 days per week, you must adjust. For example, with 4 days/week:

(365 × 4/5) - 25 - 11 - 3 = 260 working days

Deductible expenses: what you can really count

Not all expenses are deductible. Here's what the tax authorities accept:

Transportation costs:

Home-to-work mileage (official 2026 rate: €0.636 per km for a 5 CV car up to 5,000 km)
Public transportation
Professional parking

Meal costs:

Meals taken outside your home (approximately €5 to €7 per meal)
Not meals at home

Work clothing:

Uniforms or outfits specific to your profession
Not ordinary clothing

Other expenses:

Office supplies
Professional documentation
Training costs

Warning: the tax authorities may refuse expenses that seem excessive or poorly justified. Keep your receipts and supporting documents for at least 3 years.

Complete example with real 2026 figures

Imagine you're an employee in the Paris region, you work 5 days a week, and here's your situation:

Working days:

365 days - 25 vacation - 11 holidays - 2 sick days = 327 days

Transportation costs:

30 km per day × 217 office days = 6,510 km
For a 5 CV car: (6,510 × 0.357) + 1,395 = €3,719
Public transportation (2 days/week): €50 × 52 weeks = €2,600
Total transportation: €6,319

Meal costs:

217 days × €6 = €1,302

Other expenses:

Supplies and documentation: €200

Total real expenses: €7,821

With the 10% deduction, you would have deducted 10% of your gross salary. If your gross salary is €35,000, the deduction = €3,500. Here, real expenses (€7,821) are much more advantageous.

Calculate automatically with the tool

You can test the calculation directly with the associated tool. Enter your values (working days, mileage, meals, etc.) to get the result automatically. The tool also compares with the 10% deduction to show you which option is most advantageous for you.

What to remember

Real expenses can save you several hundred euros, but only if you calculate them correctly. The key step is to properly count your actual working days, then add all your justified expenses. If you're unsure, use a calculation tool to verify before filing.

How to calculate your real expenses for taxes: the complete guide

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