Five calculators for a complete property view
A property is not a single calculation but a bundle of connected items. Looking at the purchase price alone misses the cost blocks with the largest leverage. Five calculators cover the key perspectives:
| Calculator | Leading question |
|---|---|
| Mortgage calculator | What is the monthly rate and the outstanding balance after 10 years? |
| Ancillary cost calculator | How much equity goes to purchase ancillary costs? |
| Rental yield calculator | What gross and net yield does the property generate? |
| Security-deposit calculator | What is the landlord legally allowed to demand? |
| Property-tax calculator | What annual tax does the plot carry? |
Purchase ancillary costs: 8 to 12 percent, depending on state
Ancillary costs in a property purchase consist of three main blocks: real-estate transfer tax, notary/land register and broker commission. The transfer-tax rates differ by state:
| Federal state | Real-estate transfer tax |
|---|---|
| Bavaria, Saxony | 3.5 % |
| Hamburg | 5.5 % |
| Bremen, Lower Saxony, Rhineland-Palatinate, Saxony-Anhalt | 5.0 % |
| Baden-Württemberg, Hesse, Berlin, Mecklenburg-Vorpommern | 5.0 to 6.0 % |
| Brandenburg, NRW, Saarland, Schleswig-Holstein, Thuringia | 6.5 % |
Notary and land register together come to around 1.5 to 2.0 % of the purchase price. Notary fees are uniformly fixed by the German cost regulation (GNotKG). It pays off to ask for the complete fee schedule before notarisation, because extra services such as escrow accounts or cancellation orders are billed separately.
Broker commission in Germany has been split since December 2020: in the sale of a single-family house or condominium to a consumer, the seller bears at least half. Customary is a total of 7.14 % gross (3.57 % per party). In some regions a lower commission or a price-only model without a broker is also common.
A worked example for a row house in Bavaria, purchase price 500,000 €:
| Item | Calculation | amount |
|---|---|---|
| Real-estate transfer tax | 500,000 × 3.5 % | 17,500 € |
| Notary and land register | 500,000 × 1.8 % | 9,000 € |
| Broker commission (buyer share) | 500,000 × 3.57 % | 17,850 € |
| Total ancillary costs | 44,350 € |
These roughly 44,000 € have to come out of equity in most cases, because banks are reluctant to finance them ("full financing" usually becomes significantly more expensive). The ancillary cost calculator covers the state-specific rates.
Mortgage: annuity, fixed-rate period, outstanding balance
A typical German mortgage is an annuity loan with a fixed-rate period of usually 10, 15 or 20 years. The monthly payment follows from loan amount, contract interest rate and initial repayment rate:
- Payment = loan amount × (interest rate + initial repayment) ÷ 12
For 400,000 € loan, 3.5 % interest and 2 % initial repayment, this is (400,000 × 5.5 %) ÷ 12 = 1,833 € per month. The interest share falls and the principal share grows with each payment, because the outstanding balance gets smaller.
With a 15-year fixed-rate period, the key question is: what is the outstanding balance at the end?
| Year | Outstanding balance |
|---|---|
| 0 | 400,000 € |
| 5 | 357,000 € |
| 10 | 305,000 € |
| 15 | 243,000 € |
| 20 | 169,000 € |
| 25 | 81,000 € |
After 15 years a follow-up financing is due. The interest rate at that time is unknown and can differ significantly from the initial one. Starting with higher repayment early reduces this refinancing risk noticeably.
Special repayments are particularly effective in the early years. 10,000 € special repayment in year 2 saves significantly more interest over a 25-year term than 10,000 € in year 18. Many banks allow 5 to 10 % special repayment per year at no extra cost.
The mortgage calculator shows monthly payment, interest share, principal share and outstanding-balance schedule transparently.
Equity: not just a requirement, but a lever
Banks evaluate financings via the loan-to-value (LTV) ratio. The lower the LTV, the lower the interest rate. Typical bands:
| Loan-to-value | Interest surcharge (order of magnitude) |
|---|---|
| up to 60 % | base rate |
| up to 80 % | +0.15 to +0.30 % |
| up to 90 % | +0.30 to +0.60 % |
| 100 % | +0.60 to +1.00 % |
| over 100 % (incl. ancillary costs) | +1.00 % and more |
Anyone who covers ancillary costs and 20 % of the purchase price from equity does not only get a smaller loan but often a measurably better interest rate. Over a 25-year term, a 0.5 % rate difference quickly equals several tens of thousands of euros.
Rental yield: gross, net, and the difference between them
For let properties, yield is the most important metric. Three terms are common in practice:
- Gross rental yield = annual cold rent ÷ purchase price × 100
- Net rental yield = (annual cold rent − non-allocable costs) ÷ (purchase price + ancillary costs) × 100
- Equity yield = (annual surplus after interest) ÷ equity employed × 100
A sample apartment costs 300,000 €, generates 10,500 € of annual cold rent and 27,000 € in ancillary costs. Non-allocable annual costs (administration, maintenance reserve, vacancy risk) total about 2,000 €:
| Metric | Calculation | Value |
|---|---|---|
| Gross rental yield | 10,500 ÷ 300,000 | 3.50 % |
| Net rental yield | (10,500 − 2,000) ÷ 327,000 | 2.60 % |
Without looking at net yield, the property appears significantly better than it actually is. The rental yield calculator outputs both values so that you can calculate honestly.
Property tax reform 2025: three factors, several models
On 1 January 2025 the German property tax was reformed. The calculation in the federal model follows three steps:
- Property-tax value is newly assessed (via the tax office) – from land reference value, plot size, building type, living area, year of construction.
- Property-tax measurement number (legally fixed, e.g. 0.031 % for residential property).
- Municipal multiplier (very different, often between 250 % and 1,000 %).
Final formula: property tax = property-tax value × measurement number × multiplier.
Several states use alternative models:
| State | Model |
|---|---|
| Federal model | Bremen, Berlin, Brandenburg, MV, NRW, Rhineland-Palatinate, Saarland, Saxony-Anhalt, Schleswig-Holstein, Thuringia |
| Bavaria | Area model (purely based on area) |
| Hamburg | Residential-area model |
| Hesse | Area-factor model |
| Lower Saxony | Area-location model |
| Baden-Württemberg | Land-value model |
Municipal multipliers have been reset for 2025 in many municipalities – mostly revenue-neutral, occasionally up or down. The property-tax calculator helps with estimates in the federal model and reflects the key numbers from the tax notice.
Security deposit: capped at three months' cold rent
For residential leases, the security deposit is legally limited: a maximum of three months' cold rent. The tenant may pay it in three equal monthly instalments. The landlord must hold the deposit separately from their own assets, usually at the typical rate for savings deposits with three months' notice.
The security-deposit calculator computes the maximum deposit and the monthly instalments from the agreed cold rent.
Common errors in property purchases
- Underestimating ancillary costs: planning with "around 5 %" regularly misses the broker commission.
- Downplaying refinancing risk: 1.5 % repayment with a 10-year fixed-rate period leaves a large outstanding balance.
- Confusing gross and net yield: administration, maintenance and vacancy are real.
- Under-estimating property tax: it recurs and is not negotiable.
- Full financing without equity: possible, but usually significantly more expensive.
Conclusion
An honest purchase decision needs the view across all building blocks: purchase price, ancillary costs, financing, rental yield, property tax. With the five calculators on Ultra-Rechner you can run through these perspectives separately, without losing track in an overloaded all-in-one mask.
Sources
- German Real Estate Transfer Tax Act (GrEStG) – gesetze-im-internet.de/grestg_1983
- German Property Tax Act (GrStG) – gesetze-im-internet.de/grstg_1973
- GNotKG – fee schedule for notaries – gesetze-im-internet.de/gnotkg
- BGB Sections 535 ff. – tenancy law and deposit limits – gesetze-im-internet.de/bgb
- Federal Ministry of Finance – property tax reform – bundesfinanzministerium.de