Quorum requirements for a referendum to be valid

Hungary
- Mandatory referendum - turnout quorum
- Mandatory referendum - approval quorum
- Optional referendum - turnout quorum
- Optional referendum - approval quorum
Hungary'sConstitution of 2011
https://www.constituteproject.org/constitution/Hungary_2011.pdf
National referenda
Article 8
[…]
4. A national referendum shall be valid if more than half of allelectors have cast a valid vote, and shall be conclusive if more than half ofall voters casting a valid vote have given the same answer to a question.
National Election Office (website)
http://valasztas.hu/en/ovi/287/287_0.html
The conclusive referendum
A referendum is conclusive if its purpose has been fulfilled i.e.the National Assembly and the entities having initiated the referendum have gota true picture on the opinion of the country’s population concerning thequestion raised, and the population represents a sufficiently consistentposition. Our Constitution regards this for provided if more than half of thecitizens casting valid votes – irrespective of the turnout figures – but atleast one quarter of the total number of citizens eligible to vote have givenidentical answer to the question concerned.