Leading calculator manufacturer since 2011
The emergence of Calconi
As the founder of Calconi and the German website Smart-Rechner.de, we have been active on the Internet since 1995.
During this time, we have used online calculators from external providers in numerous projects. Often these were too complicated, not trustworthy
and sometimes just plain ugly. We wanted to do this better. So in 2011 we founded Smart-Rechner.de and developed a framework for the creation
of online calculators.
Now since 2020, with Calconi we also offer these useful calculators internationally.
With a love for detail, we always seek the middle road between simple operation and technical correctness. Millions of users and satisfied customers are
worth this effort. In 2018 we were commissioned by juris GmbH (Legal Information System for the Federal Republic of Germany) to provide all of the information
required for the online calculators used there and to maintain their content in the future.
Calconi - calculator manufacturer since 2011.
The founders - you can count on us

Stefan Banse 
Head of Development and Editor for Special Topics
Stefan Banse is a trained banker and studied computer science in Bonn. He was COO and member of the board for many years of Framfab Deutschland AG and has been dealing with all Internet-related topics since 1995. As key account manager for numerous major clients in the banking, insurance and healthcare sectors, he has the technical expertise to manage the Special Topics editorial department. Since 2011, he has been responsible for conception, development and quality assurance at Calconi.
E-mail to: [email protected]

Michael Mühl 
Head of Marketing and Editor for Taxes
Michael Mühl also studied computer science in Bonn and in 1995 he founded Framfab Deutschland AG, one of the largest German Internet agencies. Through his role as a major project manager for banks and insurance companies, he also acquired expertise in the area of taxes. This culminated in 2006 with his leading role in the development of Germany's first and market-leading online tax consultant, the company steuerberaten.de GmbH. Michael Mühl has been head of the Marketing and Tax Editing department at Calconi since 2011.
E-mail to: [email protected]
The team workers - our editors
For each of the 30 Calconi calculators created thus far, we write various help and advice texts. Thus, we always offer added value and assistance, since the topics of the calculators are often somewhat dry and are hard to understand.
These texts are always being adapted to the current laws and regulations. When creating the texts,
our diligent editorial team of experts in the fields of taxes, finance, medicine and law helps us.
Suggestions welcome at [email protected]
Facts and figures
- On high-volume workdays, up to 100,000 people use our calculators.
- In the last 12 months, more than 35 million people have used our calculators.
- More than 100 websites and portals have integrated our calculators.
- We are "calculator supplier" for juris - the legal information system for the Federal Republic of Germany
- In cooperation with spiegel.de and bild.de, we regularly present selected calculators on current topics to a broad public.
Actuality is crucial
The topics of the calculators live from the topicality. Many legal bases change in the course of a year. We regularly check all content and underlying details of the calculators. See the latest changes here:
September 22, 2023: Subject area Exchange rates
The pages of the 'Exchange rates' category were last editorially reviewed by Stefan Banse on September 22, 2023. They all correspond to the current status.
Previous changes on October 25, 2021
- September 22, 2023: Daily update of exchange rates in the currency converter.
- Editorial revision of all texts in this category
March 22, 2023: Subject area Convert Volts, Watts & Amps
The last changes in the 'Convert Volts, Watts & Amps' category were made by Stefan Banse on March 22, 2023. The main changes were:
- 22.03.2023: Publication of the Convert Volts, Watts & Amperes Converter together with the corresponding guides to the topics Calculate Volt, Calculate Ampere and Calculate Watt.
- Editorial revision of all texts in this category
March 14, 2023: Subject area Cylinder
The pages of the 'Cylinder' category were last editorially reviewed by Michael Mühl on March 14, 2023. They all correspond to the current status.
Previous changes on March 14, 2022
- 14.03.2023: Publication of the Cylinder Calculation together with the corresponding texts.
- Editorial revision of all texts in this category
March 14, 2023: Subject area Profit Margin
The last changes in the 'Profit Margin' category were made by Stefan Banse on March 14, 2023. The main changes were:
- 13.03.2023: Publication of the Margin Calculator together with associated texts.
- Editorial revision of all texts in this category
March 2, 2023: Subject area Discount
The last changes in the 'Discount' category were made by Stefan Banse on March 2, 2023. The main changes were:
- 02.03.2023: Publication of the Discount Calculator along with associated texts.
- Editorial revision of all texts in this category
How a Calconi calculator is created
We love good calculators, and our core business is calculators. It's not meant to sound like we have our heads in the clouds, but we have the motivation to always build the best calculators for every topic. That's why we put a lot of energy into development. We would like to briefly show you how a such a calculator is developed:



















Our customer service for you
Do you have any questions about our calculators? Are the guides difficult to understand? Is there a calculator you'd like to see? You are welcome to contact
us with any questions you may have. We look forward to hearing from you. In exceptional cases, you can simply send us a compliment :-)
Your Calconi Team - Stefan Banse and Michael Mühl
Phone: +49 221 / 177 399 40 or
e-mail to [email protected]