The most common mistakes of OSVČ just starting out

The vast majority of new OSVČ don't make one big mistake, but several small ones – and these add up. A late insurance advance payment carries a penalty for every day of delay, a forgotten statement (přehled) a fine from ČSSZ (Czech Social Security Administration) or the health insurance company, and choosing the wrong way of claiming expenses means needlessly higher tax. When several mistakes coincide, the amount can easily grow into **tens of thousands of crowns** – even for a small trader with low turnover. The good news: almost all of these mistakes have a clear cause and a simple fix. You just need to know where they happen most often – which is why we've put together the seven most common ones, along with what they really cost and where to turn to avoid them.

## 1. You don't pay advance payments from the first month – or you pay the wrong amount **Why it happens:** Many new OSVČ wait for some kind of "statement" to arrive, or mistakenly believe that no insurance is due at all in the first year. In fact, the advance payment for both social and health insurance runs from the very month in which you notified your trade. **How much it costs:** The social and health advance payments also have *different due dates* – the social one is due by the end of the current month (the July advance by 31. 7.), the health one not until the 8th day of the following month (for July by 8. 8.). The most common mistake is paying both on the same date, which puts the social advance payment into default and triggers a penalty. Since 2022 this has been based on default interest (the ČNB repo rate plus 8 percentage points) – in 2026 that works out at roughly 11.5–11.75 % a year on the amount owed, i.e. about 0.03 % for every day of delay. **How to avoid it:** Set up two standing orders with different due dates right after you notify your trade. New OSVČ also pay a lower social minimum in the first year and the following 2 years – 3,575 Kč instead of 5,005 Kč, while the health minimum stays at 3,306 Kč a month all year round. You'll find the exact amounts in [minimum OSVČ advance payments 2026](/pojisteni-osvc/minimalni-zalohy-2026) and the complete calendar in [OSVČ deadlines 2026](/dane-osvc/terminy-osvc). ## 2. You forget to file the ČSSZ and health insurer statement **Why it happens:** After the first year in business, many OSVČ don't realise they have to file **two separate income and expenses statements (přehledy)** – one for ČSSZ (Czech Social Security Administration), the other for the health insurance company. From 2026, both must also be filed electronically if the OSVČ has an accessible data box (datová schránka) – which, by law, almost everyone now has automatically. **How much it costs:** A late or entirely unfiled statement carries a fine of **up to 50,000 Kč** – for social insurance under § 25c of Act No. 589/1992 Coll., for health insurance under § 26 of Act No. 592/1992 Coll. (the authority may issue a mere warning instead of a fine) – plus a penalty on any insurance balance due, which is payable within **8 days** of filing the statement. **How to avoid it:** The statement follows on from the tax return, so keep an eye on both deadlines together – you'll find them in [OSVČ overview statements 2026](/pojisteni-osvc/prehledy-osvc). [ČSSZ](https://www.cssz.cz) also confirms the current forms and deadlines. ## 3. You choose the lump-sum expense allowance even though actual expenses would pay off (or the other way round) **Why it happens:** The lump-sum expense allowance is simple – no receipts, just a percentage of income (80 % craft trade, 60 % unrestricted, regulated and concession trade, 40 % liberal professions, 30 % rental). Many OSVČ therefore use it automatically without ever working out how much they actually spend. **How much it costs:** If your documentable expenses exceed the flat rate – typically for tradespeople buying materials or e-shops selling goods – you needlessly lose thousands to tens of thousands of crowns in tax every year. The allowance also has an **expense cap** (e.g. 1.6 mil. Kč for the 80% rate), above which it stops paying off entirely. **How to avoid it:** Before you file your return, work out and compare both options. You'll find the rates and caps in [lump-sum expense allowances](/dane-osvc/vydajove-pausaly), and details on actual expenses and tax records in [actual expenses for the self-employed](/dane-osvc/skutecne-vydaje). ## 4. You don't keep an eye on your turnover for DPH (VAT) **Why it happens:** Since 1. 1. 2025, turnover for mandatory DPH (VAT) registration has been counted per **calendar year** (January–December), not over the last 12 months as before – yet many OSVČ still count it the old way, or don't track their turnover on an ongoing basis at all. **How much it costs:** You become a payer once you exceed **2,000,000 Kč** in a calendar year, with an application due within 10 working days. If in the same year you also exceed the second threshold of **2,536,500 Kč**, you become a payer by operation of law from the very **second day** after exceeding it – regardless of whether you noticed. Late registration means a VAT assessment shortfall plus sanctions from the tax office. **How to avoid it:** Check your turnover on an ongoing basis, not just at year-end. You'll find the complete rules in [DPH (VAT) for the self-employed 2026](/dane-osvc/dph-osvc), and the procedure for filing the return in [DPH (VAT) return](/dane-osvc/priznani-k-dph). ## 5. Mixing personal and business money **Why it happens:** An OSVČ isn't legally required to have a separate business account, so plenty of beginners pay for materials and an ordinary trip to the fridge from the same card. **How much it costs:** There's no direct fine for this, but messy statements make every tax office audit longer and more expensive – you have to prove which payments were business-related, or the expense won't be recognised. With higher turnover, it also gets harder to document the actual expenses from point 3. **How to avoid it:** Open a separate account just for your business, even if it's an ordinary personal account at a different bank. Keep records diligently from day one – see [actual expenses and tax records](/dane-osvc/skutecne-vydaje). ## 6. Invoices missing required details and gaps in numbering **Why it happens:** Invoices are often knocked out "in five minutes" from a template found online, without checking whether they contain everything required – and the number gets assigned by hand, so occasionally one is missing or repeated. **How much it costs:** An invoice without the mandatory details (see [invoice requirements](/fakturace-osvc/nalezitosti-faktury)) isn't a valid document, and the tax office doesn't have to recognise the expense or income on the basis of it. A gap or jump in the number series also looks, during an audit, like a missing, unrecorded document and easily triggers a deeper investigation. **How to avoid it:** Use consistent numbering with no gaps from your very first invoice – we describe the procedure in [variable symbol and invoice numbering](/fakturace-osvc/variabilni-symbol-a-cislovani-faktur). Never delete a cancelled invoice; just mark it as cancelled and keep its number in the series. ## 7. You miss reporting a change to the Trade Licensing Office **Why it happens:** You move your business premises (provozovna), change your surname or expand your field of activity – and forget to report it, because the notification duty doesn't come to mind as an "official matter". **How much it costs:** The Trade Licensing Act requires you to report changes to the Trade Licensing Office within **15 days** of the day they occur (§ 49 of the Trade Licensing Act for notifiable trades, § 56 for concessions (koncese)). You'll also pay an administrative fee of **100 Kč** (80 Kč electronically) for a new extract with the changed details, and if the office discovers the outdated details itself, proceedings drag on and you also risk a sanction for failing to meet the notification duty. **How to avoid it:** Report the change as soon as it occurs – in person at your [Trade Licensing Office](/zivnostenske-urady), or electronically via the Single Registration Form at [rzp.gov.cz](https://rzp.gov.cz). You'll find the complete price list for all filings in [trade licence fees](/jak-zalozit-zivnost/poplatky).