What expenses can you deduct on flat tax vs tax scale?

You bought a laptop, paid for a course, had lunch with a client and made a car lease payment. Which of these lower your tax, and which will the tax office strike out of your ledger? On Poland's flat tax (podatek liniowy, 19%) and on the progressive tax scale (skala podatkowa, 12% and 32%) the answer is the same, because the catalogue of deductible costs is shared. What differs is how much tax each booked cost saves you.

The end of the year is a good moment to run the numbers. Indirect costs are deducted on the date they are incurred (art. 22(5c) of the PIT Act), so what you pay and document by 31 December 2026 lands in this year's ledger. Below are the rules, the limits and concrete numbers. We write as the makers of invoicing software, not as accountants, so confirm your own situation with your accountant.

What counts as a deductible cost: the rule and the exceptions

A deductible cost (koszt uzyskania przychodu) is an expense incurred to earn revenue or to preserve or secure its source, unless it appears on the exclusion list in art. 23 (art. 22(1) of the PIT Act). In practice three things must hold: the expense relates to the business, it was actually incurred and documented, and no rule excludes it.

The same rules apply on the tax scale and on flat tax. Under the flat-rate regime (ryczałt) you do not deduct costs at all, so this article does not cover it.

How much tax 1,000 PLN of costs saves

The catalogue is shared, but the value of a cost is not. Take a 1,000 PLN expense that lowers your income:

• Flat tax (19%): 190 PLN less income tax.

• Tax scale up to 120,000 PLN of income (12%): 120 PLN less.

• Tax scale above 120,000 PLN of income (32%): 320 PLN less.

Add the health insurance contribution, which grows with income: 4.9% on flat tax and 9% on the scale, with a 2026 minimum of 432.54 PLN a month (overview in Polish). Each 1,000 PLN of cost lowers it by roughly 49 PLN on flat tax and 90 PLN on the scale, as long as you are not already on the minimum.

In total, a cost is worth about 239 PLN on flat tax, 210 PLN in the first scale bracket and 410 PLN in the second. This is an illustration that ignores the deduction of the health contribution on flat tax. The takeaway: the same laptop costs you the least when you are in the second bracket of the scale.

Costs that usually go into the ledger

• Equipment and software. Computer, phone, monitor, licences. An asset with an initial value up to 10,000 PLN can be expensed in one go in the month it enters use; a more expensive one is depreciated (art. 22d of the PIT Act, overview in Polish).

• Services and subscriptions. Accountant, hosting, SaaS tools, advertising, training, liability insurance, bank fees.

• Office and communications. Coworking, rent, internet, phone. For mixed use, only the business share, based on a reasonable allocation key.

• Car. From 1 January 2026 the car value limit for costs (lease, rental, depreciation) is 100,000 PLN for combustion cars and most hybrids (CO2 of 50 g/km or more), 150,000 PLN below 50 g/km and 225,000 PLN for electric cars. Running costs are 75% for mixed use and 100% with a mileage log, and VAT is deducted at 50%, or at 100% after filing form VAT-26 (art. 86a of the VAT Act, full example).

• Employees and contractors. Pay and employer contributions.

What you cannot deduct

• Representation. Food, drinks and alcohol for business contacts are excluded by art. 23(1)(23) (PIT Act). Advertising is deductible, and the line is often disputed because the tax authorities read representation broadly (overview in Polish).

• Private expenses with no link to the business.

• Fines, penalty tickets and interest on tax arrears.

• VAT you deduct. It is not a cost. VAT you cannot deduct, such as the half on a passenger car, usually increases the cost.

• Cash payments above 15,000 PLN between businesses. You cannot deduct the part paid outside a payment account (art. 22p of the PIT Act).

• Your own ZUS and health contributions. They are not costs. Social contributions are deducted from income, and health contributions on flat tax are deductible up to 14,100 PLN in 2026. On the scale there is no deduction (overview in Polish).

Example: 10,000 PLN of costs on three paths

A developer running a JDG (jednoosobowa działalność gospodarcza, a sole proprietorship) buys a 6,000 PLN net laptop, a 2,500 PLN course and a year of coworking for 1,500 PLN in December. That is 10,000 PLN net, all invoiced and paid by transfer. Lowering income by 10,000 PLN gives:

• 1,900 PLN less tax on flat tax,

• 1,200 PLN less on the scale in the first bracket,

• 3,200 PLN less on the scale in the second bracket.

On top comes a lower health contribution: about 490 PLN on flat tax and 900 PLN on the scale. Net amounts apply to active VAT payers, who recover input VAT separately. If you do not recover VAT, the gross amount is the cost.

Document and timing: when a cost reaches the ledger

The basis is an accounting document, usually an invoice. Since 1 February 2026 every business receives invoices through KSeF (Poland's national e-invoicing system), so a supplier's invoice waits there with its KSeF number (Ministry of Finance schedule). From 1 January 2027 the smallest businesses, invoicing up to 10,000 PLN gross a month, must also issue invoices in KSeF. You book an indirect cost on the date it is incurred, and a cost directly tied to revenue in the year that revenue arises.

How Biurko helps with costs, and what it does not do yet

On the purchase-document side we handle what comes before the ledger:

• purchase invoices from KSeF arrive in Biurko together with the KSeF number,

• Biurko AI reads invoices from PDFs and photos for suppliers outside KSeF, and you approve each one,

• you assign cost categories and attach a contract or delivery proof to the invoice,

• your accountant gets a purchase register export and a free guest seat in your company.

What is missing: the KPiR ledger itself on the tax scale and flat tax, and the annual PIT-36 and PIT-36L. They are planned, with no date. Today your accountant or another tool keeps the ledger, and we make sure the cost document is complete and lands in the right month.

Year-end checklist

1. Collect 2026 purchase invoices and check that each has a cost category.

2. Pay by 31 December the expenses you want booked this year, and keep proof of payment.

3. Pay by bank transfer for purchases above 15,000 PLN between businesses.

4. Check that equipment up to 10,000 PLN is expensed at once and anything above goes to the fixed-asset register.

5. Separate advertising from representation.

6. Find out which scale bracket you are in before a large purchase.

Conclusion

The cost catalogue is the same on flat tax and on the scale, but 1,000 PLN of spending saves roughly 210 to 410 PLN of tax and contribution, depending on the form and bracket. A good cost has proof, a link to the business and the right month.

Biurko collects purchase documents from KSeF and from photos, categorises them and hands your accountant a ready register. Try it on your own company at biurko.io: 14 days of all features without a card.

3. FAQ

Do flat tax and the tax scale have different deductible costs in Poland?

No. A cost is an expense incurred to earn revenue or secure its source, unless art. 23 of the PIT Act excludes it. The difference is only the rate, meaning how much tax you save: 19% on flat tax, 12% or 32% on the tax scale.

Can I deduct an 8,000 PLN laptop at once?

Yes, if its initial value does not exceed 10,000 PLN. You may skip depreciation and book the expense in the month the laptop enters use. More expensive equipment goes to the fixed-asset register and is depreciated, or uses one-off depreciation if you meet its conditions.

Is a business lunch with a client deductible?

Usually not. Representation expenses, in particular food, drinks and alcohol for business contacts, are excluded by art. 23(1)(23) of the PIT Act. Advertising is treated differently, but the boundary is often disputed, so check doubtful expenses with your accountant.

Is the health insurance contribution a cost?

No. On flat tax you can deduct paid health contributions from income up to 14,100 PLN in 2026. On the tax scale health contributions are not deductible. ZUS social contributions are not costs either, but they reduce your income.

How much of a car lease can I deduct in 2026?

The capital part of the instalment up to the car value limit: 100,000 PLN for combustion cars and most hybrids, 150,000 PLN below 50 g/km of CO2 and 225,000 PLN for electric cars. For a more expensive car the cost is proportional. The interest part is not subject to this limit.