You have issued an invoice for 80 000 CZK and there is barely enough in the account to cover the office rent. That is a cash-flow problem, and it is one of the most ordinary ways for an otherwise healthy business to get into trouble. The fix is not complicated: start tracking and planning the movement of money deliberately.
This article covers why cash flow matters so much to a sole trader (OSVČ — a self-employed person in Czechia), where it usually goes wrong, and what to do about it.
What cash flow is, and why it decides things
Cash flow is simply the difference between money coming into the business and money going out. Profit is calculated from amounts invoiced; cash flow deals with what actually moved in the bank account.
Profit versus cash: the difference that catches people out
Plenty of sole traders treat the two as the same thing. Picture this:
- In March you invoiced 200 000 CZK of work
- Your monthly outgoings are 80 000 CZK
- On paper that is a profit of 120 000 CZK
- But the clients will not pay until April and May
- You have 15 000 CZK in the account and March's bills are due now
You are profitable and you cannot pay your obligations. That is the classic cash-flow squeeze, and it can end a business: you cannot pay subcontractors, rent, social security advances or VAT.
The rule to keep: an invoice issued is not income. Income is when the money is in your account. Managing cash flow means working with the real balance, not with the numbers on invoices.
Where it usually goes wrong
1. Long payment terms
A standard 14-day term stretches in practice to 30, 45 or even 60 days. Large companies tend to pay at the last possible moment, or past it. For a sole trader relying on one or two big clients, that can be fatal.
2. Irregular income
Unlike an employee with a salary date, a sole trader's income arrives unevenly. One month you invoice 150 000 CZK, the next 30 000 CZK. Outgoings stay roughly the same.
3. Forgetting what is coming
Future obligations are the ones most often underestimated:
- Income tax advances — half-yearly (15 June and 15 December) or quarterly
- DPH (VAT) — monthly or quarterly, often tens of thousands of crowns
- Social insurance — monthly advances, which can rise sharply once the annual přehled (the annual statement for social security and health insurance) is filed
- Health insurance — monthly advances on the same mechanism
- The balance of income tax — the annual reckoning in March or April can land hard
4. No reserve
Many sole traders live invoice to invoice with no cushion at all. One large client paying late is enough to bring the whole structure down.
5. Spending too much too early
Equipment, software, marketing — all of it matters, but spending heavily in one go without regard to the income side puts you straight into the trap.
How to track cash flow
None of this needs to be complicated. A few simple rules, applied consistently, do the job.
Step 1: map where you are
Start by answering these:
- How much is in the business account right now?
- Which invoices I have issued are unpaid, and when were they due?
- Which invoices I have received are unpaid, and when are they due?
- What regular outgoings are coming in the next 30, 60 and 90 days?
- What tax obligations fall due in the coming months?
In Taxorio this sits on the financial dashboard: total income, total expenses, unpaid invoices and the balance, with each invoice marked as paid, awaiting payment or overdue.
Step 2: build a cash-flow plan
A cash-flow plan is a simple table comparing expected income and expenditure month by month:
- Opening balance
- + Expected income (invoices that should be paid)
- − Planned outgoings (rent, subcontractors, software, insurance)
- − Tax obligations (VAT, income tax advances, social and health insurance)
- = Closing balance
If a month comes out negative, you know in advance and can act: ask clients about paying earlier, defer what is not urgent, or draw on an overdraft.
Step 3: watch a few numbers
- Days sales outstanding (DSO) — how long clients take to pay on average. With a 14-day term and a DSO of 35, your clients are paying 21 days late on average.
- Share of receivables past due — what percentage of your issued invoices is overdue. Under 10 % is healthy.
- Reserve in days — how many days of outgoings your current balance would cover with no income at all. Aim for 60–90 days.
Ten ways to improve cash flow
1. Shorter payment terms
Set 7 or 14 days rather than 30. On smaller jobs a short term is rarely an issue. With bigger clients it may not fly, but it is always worth asking.
2. Invoice immediately
Issue the invoice the moment the work is done. Every day of delay in issuing is a day of delay in being paid. In Taxorio an invoice takes a minute: pick the client from your list (or look them up in ARES), enter the items, send. Numbering runs automatically in a fixed YYYYXXXX format, so the sequence stays intact.
3. QR codes on invoices
Add an SPD payment QR code. The client scans it in their banking app and pays without retyping the account number and variable symbol. Taxorio prints the code on issued and overdue invoices once you enable QR payments in Settings and fill in the bank account.
4. Ask for advances
On larger jobs ask for 30–50 % before you start. It is standard practice and a reasonable client will expect it. The advance covers your own upfront costs and limits what you stand to lose if the client goes quiet.
5. Spread your client base
If 80 % of your income comes from one client, you are exposed. Aim for at least three to five regular clients, so losing one does not threaten your liquidity.
6. Build a cushion
Put money aside out of every payment as it arrives:
- 15–20 % for income tax
- 21 % for VAT if you are registered and most of your income carries it
- The social and health insurance amount
Move it to a separate account and leave it alone. When the advance or the return falls due, the money is already there.
7. Monitor unpaid invoices
Check the state of your issued invoices regularly, ideally weekly. Do not wait until an invoice is a month overdue — send a friendly reminder as soon as the due date passes. Taxorio's dashboard lists unpaid invoices with their status and flags the overdue ones.
8. Agree staged payments
On longer projects, agree milestones — say 30 % up front, 30 % after the first phase, 40 % on handover. Instead of one large payment at the end you get income throughout.
9. Review your outgoings
Go through them periodically. Paying for software you do not use? Prepaid services you no longer need? Every crown saved helps. In Taxorio you can categorise expenses (software, hardware, services, office and others) and see where the money actually goes.
10. Have a fallback
Arrange an overdraft or another short-term facility for emergencies — and arrange it while you do not need it. A bank approves it far more readily when your finances look healthy.
Tax deadlines: the biggest trap
Tax obligations are where the largest cash-flow shocks come from. Unprepared, you can be facing amounts in the tens or even hundreds of thousands of crowns.
The key dates in 2026
- Every month — social and health insurance advances
- 26 January (25 January 2026 falls on a Sunday) — VAT return and control statement for December / Q4 2025
- 1 April — income tax return for 2025 (the basic deadline)
- 4 May — extended deadline for filing the income tax return electronically
- 15 June — first income tax advance, if your last tax liability exceeded 30 000 CZK
- 1 July — extended deadline for a return filed by a tax adviser
- 15 December — second income tax advance
On top of that, VAT falls due every month or quarter, alongside the insurance advances and any instalments on other obligations. There is a tax deadline overview if you want the dates in one place.
How to prepare
Build a tax calendar and put an estimated amount against each date. Taxorio helps here with exports for the VAT return (DPHDP3), the control statement (DPHKH1) and the income tax return (DPFDP7) — the XML exports are on the PRO plan; the dashboard shows the VAT you are currently on the hook for, so you can plan ahead.
Tip: open a separate savings account, call it "Tax", and move the estimated share for tax and insurance across the moment each payment arrives. When the deadline comes the money is waiting and there is no shock.
A worked example
Take a freelance web developer, a sole trader registered for VAT, at the start of April 2026.
The position:
- Account balance: 45 000 CZK
- Unpaid invoices: three, totalling 180 000 CZK, all due in April
- Obligations: office rent 12 000 CZK, software 3 500 CZK, insurance 2 800 CZK
- VAT for March, due 25 April: 28 000 CZK
- Social insurance advance: 5 720 CZK
- Health insurance advance: 3 306 CZK
Total outgoings in April: 55 326 CZK
There is 45 000 CZK in the account against 55 326 CZK of obligations — a shortfall of 10 326 CZK. At least one invoice has to be paid by mid-month.
What that looks like in practice:
- Check the unpaid invoices on the dashboard
- Single out the one for 48 000 CZK, due 8 April, as the priority
- Send the client a note about the approaching due date, with the QR code for a quick payment
- The client pays on 9 April, and the problem never becomes one
Without that monitoring, the shortfall would have surfaced on the day the VAT could not be paid — with late-payment interest from the tax office attached (ČNB repo rate + 8 percentage points).
Tools
You do not need complicated software. You need to know three things: how much you have, how much clients owe you, how much you owe. Taxorio's financial dashboard puts them in one place:
- Total income for the chosen period
- Total expenses broken down by category
- Unpaid invoices with their due dates, overdue ones marked
- VAT overview — how much you have collected and how much you will pay
A regular look at it, ideally weekly, gives you an honest picture of the financial state of the business. Knowing where you stand is what lets you decide on the facts rather than on hope.
Cash-flow management is not about elaborate financial models. It is about discipline, regularity and reacting in time. Start with the basics above and the business gets steadier.
Taxorio scope: Taxorio provides invoicing and income/expense records for Czech sole traders. It is not full accounting or personalised tax advice. For an unsupported or unusual case, verify the treatment with a Czech accountant or tax adviser before filing.