A rented flat with a mortgage looks worse than it is if you only check whether the rent covers the monthly payment, and better than it is if you count everything the tenant pays as income. The honest view splits the mortgage payment in two: interest is a cost of the flat, principal is money you move into your own equity. Rent minus owner costs minus interest is your rental result. Service charges you pass on to the building and the tenant's deposit are neither income nor cost. With a recent Czech mortgage, most flats show a small loss on that line while building equity every month, and that is fine as long as you know both numbers.
This article walks through a worked example, the four items people most often misread, what changes at refixation, how the rental income tax choice works, and how the new Properties and Loans sections in MoneySky track all of it.
A worked example
An illustrative flat, not a real one: bought and valued at 6,250,000 CZK, with a 5,000,000 CZK mortgage at 4.8% fixed, repaid over 30 years. The bank takes 26,233 CZK a month. The tenant pays 18,000 CZK rent plus 3,000 CZK of service advances. The owners' association (SVJ) charges 4,200 CZK a month, of which 3,000 CZK covers services used by the tenant and 1,200 CZK goes to the repair fund. Property tax is 1,500 CZK a year.
Looking only at your bank account, the month goes like this:
| Cash view | CZK per month |
|---|---|
| Received from the tenant (rent and service advances) | 21,000 |
| Mortgage payment | −26,233 |
| SVJ advances | −4,200 |
| Property tax (1,500 a year) | −125 |
| Difference on your account | −9,558 |
Minus 9,558 CZK a month feels like a flat that costs you money. Now the same month, split by what each payment actually is:
| Economic view | CZK per month |
|---|---|
| Rent | 18,000 |
| Owner costs (repair fund 1,200, property tax 125) | −1,325 |
| Net operating income | 16,675 |
| Mortgage interest | −20,000 |
| Rental result | −3,325 |
| Principal repaid, added to your equity | 6,233 |
| Service advances received and passed on | 0 |
The flat costs you 3,325 CZK a month, not 9,558. The other 6,233 CZK is saving: it reduces your debt and stays yours when you sell. In the first year that adds up to 76,467 CZK of principal and 238,332 CZK of interest. The interest share falls with every payment, so the rental result improves over time even if nothing else changes.
One more number is worth knowing. The net yield here is 16,675 × 12 / 6,250,000 = 3.2% a year, below the 4.8% mortgage rate. At this rate the borrowed money costs more than the flat earns, so the investment relies on principal repayment and on the price of the flat going up. That can be a perfectly good plan, but it should be a conscious one.
Four things that are not what they look like
Principal is not a cost. It is a transfer from your bank account into your equity. Counting the whole mortgage payment as an expense makes a rented flat look far worse than it is.
Service advances are not income. If the tenant pays you for services and you pass the money on to the SVJ, it only flows through. What matters is the balance: if the annual settlement shows an overpayment, part of it belongs to the tenant.
The deposit is not income. A deposit (kauce) is money you owe the tenant back. It belongs on the liabilities side, next to the mortgage.
Interest is not fixed forever. Czech mortgages are fixed for a few years at a time. After five years the example loan still has 4,578,256 CZK outstanding. Refixed at 5.8%, the payment rises by 2,707 CZK to 28,941 CZK. At 3.8% it falls by 2,570 CZK to 23,663 CZK. The rental result moves by roughly the same amount.
Rental income tax: 30% flat expenses or actual expenses
Rental income is taxed under §9 of the Czech Income Tax Act. Each year you choose one method for all your rentals: flat expenses of 30% of the rent, capped at 600,000 CZK a year, or actual expenses, which include mortgage interest, owner costs and depreciation of the flat.
In the example, a year of rent is 216,000 CZK. With flat expenses, 151,200 CZK is taxable, which is 22,680 CZK of tax at 15%. With actual expenses, the first year's interest alone, 238,332 CZK, is more than the rent, before property tax and depreciation are even counted. With a recent mortgage, actual expenses usually come out better, and the comparison is worth repeating every year as the interest falls.
This is a simplified illustration, not tax advice. Depreciation, improvements and losses have rules whose details depend on your situation.
How MoneySky tracks it
MoneySky now has two new sections under Assets: Properties and Loans.
Properties. Record a flat, house, land, garage or commercial property with its purchase price and your ownership share, including co-owners such as a partner. Mark the periods when it was your own home, rented, partly rented or vacant. The property page shows value, loan balance, equity, loan to value, the next refixation and a profit and loss table with rent, owner costs, net operating income, interest, rental result and principal repaid. Switch between your share and the total.
Valuations. Add the purchase price, your own estimate or an appraisal. For flats in Czechia, MoneySky can also update the value every quarter from the regional flat price index published by the Czech Statistical Office, starting from a valuation you entered.
Loans. A mortgage, building savings loan, car loan or consumer loan with its rate periods, payment day and term. MoneySky builds the repayment schedule, splits every payment into interest and principal, checks the balance against your bank statement, takes the interest certificate your bank issues each year and records extra repayments that shorten the term or lower the payment. Revolving credit and leasing are tracked by balance only. Four months before a fixation ends, you get a reminder.
Linking payments. Start from your recurring payments: pick the mortgage, the rent and the SVJ advances, say what each one is, and MoneySky turns that into rules. Every mortgage payment is then split into interest and principal automatically, rent is split into rent and tenant services, and a deposit stays a liability. Anything paid outside your connected accounts, such as a kitchen bought with the flat, goes in as an off account entry.
The rest of the app. Monthly cash flow shows properties and loans as separate lines and counts principal repaid as saving. Net worth includes the flat at your share, minus the loans and tenant deposits. Budgets can follow a single property or loan.
Tax. The Tax tab compares actual and flat expenses at your tax share, handles depreciation and improvements, and recommends a method for the year. On the Everything plan the figures flow into the rental income section of your personal income tax return (DP7). When you sell, a sale review checks the exemptions for living in the flat and for the holding period.
Your AI assistant. Properties and loans are available to Claude and ChatGPT through the MoneySky MCP connection, so you can ask "what did the flat earn this year after interest?" and get the answer from your own data. Read how the assistant connection works and what is safe.
FAQ
Is the mortgage payment an expense?
Only the interest part. Principal reduces your debt and increases your equity, so MoneySky counts it as saving.
Can I track a flat I own with my partner?
Yes. Set the ownership shares, and every figure is available for your share or for the whole property. Loans linked to the property take the same shares unless you set them differently.
What happens when my fixation ends?
MoneySky reminds you four months ahead. Once you agree the new rate with the bank, add it as a new rate period and the schedule and the rental result update from that date.
Does it work for property outside Czechia?
Tracking works for any country and currency, including loans in a foreign currency. Automatic value estimates and the rental tax panel are for Czech property in CZK.
Which plans include it?
Properties and loans are part of the Personal plan (€3.99 a month) and the Everything plan (€9.99 a month). Filling the rental income section of your tax return is part of Everything.
Every plan starts with a 14-day free trial of everything, no card needed. Add your flat, link the mortgage and the rent, and see what it really earns. Compare plans.