Currency in use in Czech Republic

For the best exchange rate and to save money the best practice is to take Czech Koruna out of an ATM attached to a bank during business hours using your debit card when you get to the Czech Republic which is not on the Euro.

https://thebanks.eu/countries/Czech-Republic/major_banks

When we were there precovid, most stores had prices in both Euros and the local currency, so accepted both.
Safe travels!

But it you priced out the two prices, the euro was always higher and never to your advantage to use euro. If you are off a river cruise and buying ice cream, then the difference is small and not worth the effort to obtain local currency.

When we were there precovid, most stores had prices in both Euros and the local currency, so accepted both.

We have spent several weeks in Prague over two trips and have always used Czech koruna. Most stores and restaurants we went to only had prices in koruna. We stayed in the Vinohrady district.

Thanks to all. We will bring both koruna and euros.
We are going to Vienna afterward. When I priced the trainfare for the trip from Prague to Vienna, it was higher if I would book through the Austrian rail site rather than through the Czech rail site. Same train, same class of travel, different fares.

it was higher if I would book through the Austrian rail site rather than through the Czech rail site. Same train, same class of travel, different fares.

Nothing new here, the same train on different national websites will never have the same prices.

You probably will not spend any Euros in Prague. Even if somebody accepts them the minimum will be a 5 euro note i.e. they won't accept coins and it's a crap exchange rate and you get change in CZK. If you see prices listed in Euros it is normally accompanied by a little sign that says something like "Prices in EUR are only for guidance" etc. 1 Euro coins are good for public toilet entry machines.

The Euro is a foreign currency in the Czech Republic - business is denominated in Koruna.

Thanks to all for the excellent answers.
Another question: How widely are credit cards accepted in Prague?

https://www.mzv.cz/tokyo/en/visas_and_consular_info/faq/index.html

It's a CZR Consular website ignore the Japan part.

You'll find VISA/MASTERCARD is widely accepted here but not so much Diners Club and AMEX but I do agree with the MZV link above that not all restaurants take credit cards even in the capital especially after the pandemic. As a rule, always check with the staff if your method of payment is accepted. Then pay the bill by card if you can but have enough cash on hand to cover the bill just in case. If you have "contactless" payment cards you'll use the all the time. Public transport ticket machines will not accept cards that do not have either the contactless option or a chip/PIN.

Another question: How widely are credit cards accepted in Prague?

Everywhere.

Thanks to all.