This cannot be answered without first expanding the question:
- Vingt means 20 in French so the currency is not called the Vingt Franc - you are not talking about 20 Vingt Francs. You are talking about having 20 Francs. The confusion may arise as a note may have both the number 20 on it and the words 'vingt francs'.
- France has not used the Franc since 1995 when it adopted the Euro. The Euro is one of the most powerful currencies in the world, only behind the US Dollar in many statistics. It is used by 17 of the 27 member states of the European Union. These are Austria, Belgium, Cyprus, Estonia, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, Malta, the Netherlands, Portugal, Slovakia, Slovenia and Spain.
- So when we are talking about 20 Francs and their value in American money, it is unlikely that we are talking about French currency, even though the word vingt is French.
- If we are talking about the old French Franc though and its approximate value against today's American dollar, a rough calculation can be made. When France adopted the Euro, there were around 10 French Francs to the British pound. A British pound is currently valued at around $1.60. Therefore 20 French Francs would be worth around $3.20 if it was still a currency in use.
- The only version of the Franc that is still in use is that of Switzerland. The 20 note you are talking about is most likely one of these. The Swiss note has both the number 20 on it and the term 'vingt francs'. This is because the country has three main linguistic and cultural regions - German, French, and Italian.
- If it is indeed 20 Swiss Francs that we are talking about, the value would be around $24 as one dollar is currently worth 0.83 Swiss Francs.