How Stripe fees work
A Stripe fee has two parts: a percentage of the transaction and a fixed fee on every successful payment. On a Polish account, a card issued in the European Economic Area costs 1.5% + 1.00 zł. The percentage scales with the amount, the fixed fee does not — and it is the fixed fee that decides how much you really give up on small transactions.
The headline rate tells you less than you think, because it describes only one of the two parts of the bill. The number worth comparing is the effective rate: the whole fee divided by the transaction amount. That is the one that shows what share of a sale the payment processor keeps.
Take a 1 000 zł transaction. 1.5% is 15.00 zł, plus the 1.00 zł fixed fee — 16.00 zł in total. You receive 984.00 zł, and the effective rate is 1.6%. Almost exactly what the pricing page promises.
Now take a 20 zł transaction. The percentage is only 0.30 zł, but the fixed fee is still 1.00 zł. That is 1.30 zł in total — 6.5% of the sale. Same headline rate, more than four times the real cost.
So if you sell cheap subscriptions, micropayments or small add-ons, your real cost is not the percentage — it is that one zloty on every payment. The calculator above computes both parts separately and shows the effective rate so you do not have to guess. It also projects what you pay monthly and yearly at your transaction volume, where the gap between 1.6% and 6.5% stops being abstract.
It works in reverse too. If you need a specific amount to land in your account, adding the fee to the net amount is not enough — the fee is charged on the gross amount, the larger one, so the naive approach always falls short. The correct formula is (target amount + fixed fee) ÷ (1 − rate), and "I want to receive" mode applies it for you.
What pushes your fee up
1.5% + 1.00 zł is the base case, not the ceiling. Here are the mechanisms that raise the bill, and what actually triggers each one.
A card issued outside the EEA — 3.25%. What matters is where the card was issued, not where the customer lives or which currency they pay in. A customer in Warsaw paying with a card issued in the US is an international transaction as far as Stripe is concerned. On a Polish account that costs 3.25% instead of 1.5% — more than double. On eurozone, Czech, Hungarian and UK accounts the same category is 3.15%.
A card issued in the United Kingdom — 2.5%. This is a tier of its own: neither the EEA rate nor the international one. On an EEA account, a UK-issued card costs 2.5%. If you sell into the British market, it is worth knowing you are not paying the full international rate on those transactions — but you are not paying the domestic one either.
A premium or commercial EEA card — 1.9% in Poland. Here is the surprise that is easy to miss: in the rest of the EEA, Stripe charges 2.8% for these cards, and on a Polish account 1.9%. Poland is distinctly cheaper in this category, against the intuition that rates east of Germany must be higher. If you sell B2B and your customers pay with corporate cards, that difference is one of the stronger arguments for keeping your Stripe account in Poland.
Currency conversion — an extra 2%. If you charge the customer in a currency other than your account's settlement currency, Stripe adds 2% to the rate. It is an add-on, not a replacement — it stacks on top of the card rate. The most common setup: prices in euro, account in zloty.
Stripe Invoicing — an extra 0.4%. Standalone invoicing in Stripe is billed per paid invoice: 0.4% on the Starter plan, 0.5% on Plus. That fee has no cap — and it is the part of the pricing most often confused with something else. More on that below.
Stripe's hidden fees
The calculator covers the per-transaction fee, because that is the one that touches every sale. But a Stripe bill also has lines that show up less often, which is exactly why they surprise people.
Two different invoicing fees, not one. There is a widespread belief that invoicing in Stripe costs "0.4% capped at 2 USD". That is two separate products fused into one claim. Standalone Stripe Invoicing is 0.4% per paid invoice (0.5% on Plus) and has no cap whatsoever — on a 50 000 zł invoice you pay the full 0.4%. The 2 USD cap (or its local equivalent) applies to post-payment invoices issued through Checkout and Payment Links, where the rate is 0.4% capped at 2 USD. If you budget on the cap while actually using standalone Invoicing, the bigger your invoices, the more wrong you will be.
A dispute received — 90.00 zł. You pay this simply for receiving the dispute, before anything is decided. On low-value transactions, one dispute can eat the fees from dozens of successful payments.
Radar — from 0.23 zł per screened transaction on pay-as-you-go. The plans that actually exist are Radar Lite, Radar Standard, Radar Plus and Radar Pro. We say that plainly, because some comparisons list a per-transaction fee for a plan called "Radar for Fraud Teams" — no such fee is published. If you see a specific figure attached to that name, it did not come from Stripe's pricing.
Instant Payouts — 1%, minimum 2.00 zł. A standard bank payout costs nothing; you pay only to have the money arrive immediately. The minimum means the effective cost on small payouts is noticeably higher than 1%.
Stripe Tax and Stripe Connect. We deliberately put no figure on these. Stripe Tax calculates and reports sales tax, Connect handles payouts to sellers on a platform — both are priced by plan, country and usage, and we publish only numbers that can be read unambiguously. Check the current terms on Stripe's pricing page.
How to lower your fee
Card rates are given and you do not negotiate them at low volume. But three of the four parts of the bill depend on how you set up your sales, not on what the customer pays with.
Settle in your customer's currency. The 2% conversion surcharge is the easiest line to remove: if you sell in euro, hold a euro balance and pay out to a euro account. The add-on disappears because there is nothing left to convert.
Offer local payment methods. BLIK and Przelewy24 are priced differently from cards — calculated on a different basis and independent of where a card was issued. For Polish traffic it is worth checking their terms on Stripe's pricing page and letting customers choose.
Raise your average transaction value. This is the 20 zł example working in your favour: the fixed fee dominates small amounts. An annual plan instead of a monthly one, a bundle instead of a single line item, a higher minimum basket — each of those spreads that one zloty over a larger sale.
Do not pay 0.4% for invoicing you do not need. If another system issues your invoices anyway, standalone Invoicing adds an uncapped percentage to something you have already solved. Check that you are actually using what you are paying for.
Stripe fees and your KSeF filing
You pay Stripe for moving money — for accepting the card, authorising, settling and paying out. The obligation to issue a structured invoice and file it with KSeF is a separate matter: Stripe takes its fee whether or not the invoice reached KSeF, and KSeF does not care what you paid your payment processor.
Which is why we bill differently. KSeF Kit is a flat monthly subscription and adds nothing per transaction. It makes no difference whether you sold for 20 zł or 20 000 zł, or whether the customer paid with an EEA card or an international one — filing an invoice costs the same. Your effective rate does not rise because of us, because there is no per-transaction cut on our side.
How it works in practice: an invoice finalized in Stripe becomes an FA(3), goes to KSeF, and the KSeF number and UPO come back to the invoice. See the Stripe KSeF integration, or, if you want to try it without a card first, free KSeF for Stripe.
The rates in the calculator come from Stripe's official pricing pages and were checked on 30 July 2026. The calculator is informational — Stripe's own pricing is what binds.