Guide · Valuation and data

Comparative value method: use comparable purchases correctly

Updated on 04.10.2026 · 5 min read

The comparative value method, explained: choosing suitable transaction prices, checking property features and making adjustments, and how this differs from comparing public asking prices.

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Contents · 5 Sections
  1. 01Basic idea: suitable cases instead of simple averages
  2. 02Which features are important?
  3. 03Calculation example: no current market valuation
  4. 04Asking prices are not comparable transaction prices
  5. 05When do you need a specialist?

By DDORF WOHNEN · Software development and editorial work. General information, not advice on your individual circumstances.

01Basic idea: suitable cases instead of simple averages

The comparative value method starts with suitable transaction prices. Comparable properties should resemble the property being valued in the characteristics that affect value. Significant differences need appropriate adjustments; a similar floor area alone does not make a transaction comparable.

02Which features are important?

Check property type, location, plot or apartment characteristics, condition, construction year, rights and valuation date. An unrenovated apartment and a modernised one in the same building can have different values. Do not add a blanket adjustment for a feature already accounted for by the model.

03Calculation example: no current market valuation

Three illustrative comparison values of 2,900, 3,000 and 3,200 €/m² have a median of 3,000 €/m². Multiplying by 80 m² gives 240,000 €. Without checking comparability and the adjustments required, that figure is not a reliable market value. These numbers illustrate the calculation; they are not taken from current sale contracts.

04Asking prices are not comparable transaction prices

Public asking prices are what the respective provider is asking and do not show the purchase price actually paid. An official reference value, in turn, is a value for a described typical property. Check whether it suits your purpose and which adjustments are needed. This guide provides neither an individual purchase price check nor a valuation report.

05When do you need a specialist?

If a specific value needs to be proven to a court, tax office or contractual partner, first clarify the requirements. A suitable specialist decides on data selection, procedures and scope. If necessary, obtain appropriate information about the purchase price collection and check the terms of use. An online result should not subsequently be described as an official report.

No legal or tax advice

General guidance, no individual valuation and no legal or tax advice.

Next steps and background

Data sources

Official source · Our own calculation · Our own analysis · DDORF estimate → Methodology

As of · Legal information: 10/2026 · Source: DDORF WOHNEN editorial team