Make a backup first! And test first in develop environment.
To convert all prices from net (german: netto) to gross (german: brutto) ones, you need to issue the following SQL statement.
But at first you need to obtain your attribute_id of the
price attribute. To do so, go to backend > stores > attributes > product and click on the
Obtain the id from the URL (see screenshot below):
In this case it is
67 but yours can be different!
Update catalog_product_entity_decimal set value = ROUND(value*1.19, 2) WHERE attribute_id = #your_attribute_id#
#your_attribute_id#would be your previously obtained attribute_id of the
price attribute (in this case
This query will also round your prices! F.e. if your net price was
19.3193 the result will be
If you have special prices on some of your products, you do need to repeat the above steps for the attribute_id corresponding to the attribute
Do not forget to set your catalog prices to
including tax. Afterwards reindex prices via cli
php bin/magento indexer:reindex.