This app was developed primarily as a free help and support for the customers of DENS GmbH. DENS is known for its popular dental software DENSoffice and various services in the dental sector. However, the app can be used by anyone who often has to calculate prices from gross to net or vice versa.The VAT rates were changed as follows: 19% became 16% and 7% became 5%. The whole thing should be reversed in 2021 and so the app will help again here.In doctors and dental practices, purely medical and dental services are exempt from VAT, but VAT must generally be levied on purely cosmetic services and so-called demand services. This also applies to the products that are sold in a prophylaxis shop. The app helps dental staff or dentists and their practice staff with the correct conversion.The idea for the app arose spontaneously when a temporary VAT reduction was decided in Germany for 2020, which meant that many prices of products and materials had to be recalculated.