Leading calculator manufacturer since 2011

Online calculators of Calconi
Stefan Banse, Founder
We love good online calculators!

So we became "calculator supplier" for juris - the legal information system for the Federal Republic of Germany
Stefan Banse, Founder

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 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

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 Smart-Rechner.de.
E-mail to: banse@calconi.com


Michael Mühl

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 Smart-Rechner.de since 2011.
E-mail to: muehl@calconi.com

The team workers - our editors

Editorial office Calconi For each of the 7 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 editorial@calconi.com

Facts and figures

We are truly happy about our users and visitors. Even after many years, we look almost daily with curiosity at the statistics to see how often our calculators are used. We are the proud market leader in Germany. Some impressive numbers:
  • On high-volume workdays, up to 100,000 people use our calculators.
  • In the last 12 months, more than 25 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.
Online calculators of Calconi
Bad calculators annoy me!

That is why we always pay attention to quality in detail. Only when a calculator is easy to use for everyone are we satisfied.
Michael Mühl, Founder
Michael Mühl, Founder

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:

November 26, 2020: Subject area Calorie requirement

The pages of the "Calorie requirement" category were last editorially reviewed by Stefan Banse on November 26, 2020. They all correspond to the current status.

Previous changes on June 25, 2020

  • January 1, 2020: Publication of the calorie calculator.
  • Editorial revision of all texts in this category

November 22, 2020: Subject area Units of length

The last changes in the "Units of length" category were made by Stefan Banse on November 22, 2020. The main changes were:

  • November 5, 2020: Publication of the Length converter
  • Editorial revision of all texts in this category

November 22, 2020: Subject area Units of speed

The pages of the "Units of speed" category were last editorially reviewed by Stefan Banse on November 22, 2020. They all correspond to the current status.

Previous changes on November 9, 2020

  • November 9, 2020: Publication of the Speed converter
  • Editorial revision of all texts in this category

June 25, 2020: Subject area Units of weight

The last changes in the "Units of weight" category were made by Stefan Banse on June 25, 2020. The main changes were:

  • Publication of the Weight converter
  • 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:

Idea from users or customers
We still have many calculators on our own list that we would like to develop. We frequently receive suggestions for new calculators from users or customers. We are always happy to receive these. There is a need, we seize upon the suggestion and consider it for development.
Research and feasibility
Now our development department begins its work. We research whether there are already corresponding calculators and familiarise ourselves with the legal regulations if necessary. Even at this early stage, experts from a wide variety of disciplines, such as tax law or specialised fields of medicine, are consulted if necessary. If the topic can be represented in a calculator and if the demand is high enough, the decision to develop the calculators is made.
Rough concept
A big challenge is always finding the optimum compromise between user-friendliness and 100% legal correctness. Some topics would by law result in a calculator that could only be operated by absolute experts. This often makes no sense. We always strive to find the happy medium and thus create maximum added value. Should we decide against developing the calculator, we will, of course, communicate this. This is the work that is performed while developing the basic concept.
Input mask for the data
After researching which data are required for the calculation, we display them in an intuitive input mask. Different data require different input elements. Of course, the calculators also need to work on mobile devices. During the design phase, we make our first notes about which help texts the individual elements require.
Calculation logic
Once it is determined which input data is available, the calculation logic is created. A stringent error query is necessary here. Many people rely on our calculators. As a result, very strict quality assurance is necessary. The calculation logic is usually simulated in Excel and then implemented in the programming language.
Result output
Not only the input of the data needs to be intuitive but also the output of the results as well. Too much result data can quickly become confusing. Here, too, we plan which data our users might expect. In addition, we visualise the most important results in graphic charts.
Help texts
This issue is very close to our hearts. We spend a great deal of time on preparing intuitive help texts, as they can decisively change how a calculator is used. We describe both the input fields as well as the individual aspects of the result. To make the whole thing easy to understand, our help texts always contain the concrete calculation steps with your input data.
Supplementary advice texts
During the creation of a calculator, we automatically encounter special topics related to the calculator. Our expert editorial team picks up on these topics and prepares suitable advice texts on the subject area.
Test, test test
Now a another internal quality assurance step takes place. We form a small team of people who were not involved in the development of the calculator. These people test all possible test scenarios and make a corresponding comparison with the laws or other available sources on this topic. Possible errors are corrected immediately.
Expert review
Internal quality assurance is followed by external quality assurance. The calculators are checked by external experts. Depending on the calculator, these are tax consultants, employees of tax publishing houses, customers from the insurance and banking sectors, or external physicians and doctors in the medical field. Only after this final examination are our calculators allowed to go online. Such a launch is always a very special moment for the entire team.
Feedback loops from users and customers
Of course, we make mistakes, too. Fortunately, our users and customers think along with us and we are very grateful when we are made aware of possible errors. If the errors are confirmed after the review, we fix them on the same work day in most cases.

Our customer service for you

Customer service Calconi 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 info@calconi.com