Almost nobody runs a business today without a phone, an internet connection and a handful of software subscriptions. The good news is that all of it can be a tax expense. The complication is that if you also use these things privately — and most people do — you have to work out the split and be able to justify it. Here is how each part works.
Phone: the whole thing, a share, or nothing
A mobile phone is the textbook expense that bleeds into private life. There are three approaches.
1. A phone used only for business
If you keep a second handset purely for work, you can claim the full tariff and the full purchase price of the device. It is the cleanest option from a record-keeping point of view, and in practice the rarest.
2. A proportional share
If one phone serves both purposes, you claim only the business share — typically 50 % or 80 %, depending on how you actually use it. You need to be able to justify the figure; a reasoned estimate recorded at the time is usually enough, an unexplained number is not.
Example: a monthly tariff of CZK 900 with 70 % business use gives a deductible expense of CZK 630 a month, or CZK 7,560 a year.
3. Flat-rate expenses
If you claim flat-rate expenses (80 % of income for craft trades and agriculture, 60 % for other trades, 40 % for other self-employed income under § 7), the phone and the internet are not a separate question at all — they are already inside the percentage. That is the general rule: under the flat rate you cannot add individual expenses on top.
If your phone, internet and software together come to a few thousand crowns a year and you are on flat-rate expenses, IT costs alone are rarely a reason to switch to real expenses. If you are paying thousands a month for software, the calculation looks different — our comparison of flat-rate versus real expenses runs the numbers.
Internet: the home connection
The internet works much like the phone. A home connection used for both work and private life is claimed as a proportional share — typically 50 % to 80 %. The key requirement is that the invoice is in your name or your IČO, not a flatmate's or a partner's.
A separate business connection, in an office you rent or at your place of business, is fully deductible.
Software as a service
More and more tools have moved to subscriptions — Microsoft 365, Adobe Creative Cloud, project tools, CRM systems, invoicing software. For tax purposes this is the simple case:
- A monthly or annual SaaS subscription is a deductible expense in the period you pay it
- There is no asset to register and nothing to depreciate — it is an operating cost
- The condition is business use; if you also use it privately, the proportional rule applies again
What this looks like in practice
- Microsoft 365 Business: roughly CZK 350–500 a month, fully deductible for business use
- Adobe Creative Cloud: roughly CZK 1,300 a month for designers, deductible
- Figma, Notion, Asana, Slack: deductible where used for work
- Taxorio: a subscription to invoicing and records software is a deductible expense like any other
- Antivirus and backup services (Dropbox, Google One): deductible for business use
Which category in Taxorio
Two categories cover almost all IT spending:
- Phone and internet — mobile tariffs, landlines and data connections, including a home connection you claim proportionally
- Software and licences — software purchases, SaaS subscriptions, licences, apps
Physical kit goes under Hardware and equipment. Getting the category right is what lets you filter IT spending later and see what you actually pay for digital tools over a year — the full list is in our guide to the expense categories.
If a category is always mixed use for you, set it once: in Settings, Default business use by category lets you store a percentage — say 70 % for Phone and internet — and every new expense in that category is pre-filled with it. You can still override it on an individual document.
Hardware: expense now or write it off?
Buying physical equipment — a laptop, a monitor, a printer, a phone — follows a different rule from software.
Up to CZK 80,000
Property with an acquisition value up to CZK 80,000 (the threshold since 2021) is claimed in tax records as a one-off expense in the year of acquisition. No depreciation, no asset card — the whole amount at once. That covers most laptops, monitors, phones, printers and other small equipment.
Over CZK 80,000
Professional photographic equipment, server hardware or a specialised machine above CZK 80,000 is long-term tangible property. It goes into a depreciation group and is written off over the period set for that group — 3 or 5 years depending on the group (§ 30 of the Income Tax Act). You cannot claim it in one go.
Taxorio does not keep asset cards or calculate depreciation — an expense above the threshold stays in your records at its full amount and is flagged for you to handle. Work the depreciation schedule out with an accountant, and be careful not to claim the same purchase twice.
Mixed use applies here too
If you use a laptop 80 % for work and 20 % privately, only 80 % of the purchase price is a tax expense. Record the split when you buy it, while you still remember the reasoning — reconstructing it two years later in front of an inspector is not a position you want to be in.
Recording it properly
- Collect the documents — an invoice, or a bank or card statement, for every expense
- Decide the business share — for mixed expenses, note the percentage and why; a single line is enough
- Record it in Taxorio under the right category: Phone and internet, Software and licences, or Hardware and equipment
- Above CZK 80,000, agree the depreciation schedule with your accountant before the year closes
Kept this way, the year-end gives you your total IT spending broken down by category — which is what the tax return needs, and also the clearest answer to how much your digital tools are really costing you.
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.