50th birthday to Paris Athens Mykonos in September

how much I might need

How high is up?

Currently the US dollar is strong against the Euro and I was wondering if I should buy some now?

No, it's not, and no you shouldn't.

First, I wouldn't call the current US dollar particularly "strong" against the Euro. I've seen worse and I've seen better (here's a chart of exchange rates over the last 5 years). Second, international currency speculation is not a game I would want to play - unless you have some very solid insider information - that's very risky and like going to Vegas but without the all-you-can-eat food. Third, "buying Euros" in the USA is almost always an expensive (and needless) option - the fees you would pay for that would very likely cost you many times more than any gains you might realize if your currency speculation "bet" (and that's what it is) comes out in your favor. Do the sensible thing: first forget gambling on the exchange rate, and just pull Euros out of an ATM upon your arrival in Europe.

could you give me an educated guess as to how much I should bring along with how much I might need?

Nobody can tell you how much you will need. But yes, I can tell you how much to "bring with you" from Chicago: none.

Well, OK, I usually bring a few hundred dollars in cash - in US dollars - for an emergency; I think that's about right for most people, but that's not money you should spend unless you have a bonafide emergency. More to the point: don't "buy money" here and bring it to Europe. For actual spending money, get Euros in Europe, using your ATM debit card linked to your US bank account.

The above posts are spot on.

For more about money, here's Rick's page of excellent tips. Read all the links, and you'll be an expert: https://www.ricksteves.com/travel-tips/money

Since you were last in Europe before the introduction of cash euros, one thing you'll appreciate is how much easier it makes things. You won't have to be converting from dollars to francs to drachmas, then wondering what to do with leftover drachmas at the end of your trip. You'll just get euros from ATM's, and use these for both France and Greece. Any leftover euros at the end can be saved for a future trip. If you don't end up going on a trip soon, you can sell them to someone who is going anywhere in the euro-zone.

Hello to all,
I thank you for your responses. I really didnt want to get into the strength of the US dollar vs Euro what I need was what all is necessary and I got that answer. I will also be bringing $200 US because Ive been to Europe when they have had strikes and its no joke.
My main concern I guess is 12 actual days in Europe Id just wanted a ball park figure for the amount of money needed.Yes Im happy that I wont have to worry about drachmas. francs...etc.
Rick has some serious travelers in this group and I appreciate the help.
I managed to get good rates on the flight and hotels but the money amount in Paris is what has me concerned. It will be my 3 time in Athens so not so concerned about that and I know that Mykonos has become even more expensive than ever but I do love it:)
Sincerely Maureen