Free trip on swiss flexi pass?

Hi, I am a bit confused when I read about a "free day" of travel on the swiss flexi pass. Does this mean if we are making 4 trips we only need to buy a 3 day flexi pass? I have had some replies and read some replies to others that refer to a "free day" and i am not sure what that means. Thank you to anyone who can clarify!
Lisa, confused in Boston

Perhaps what I should ask is if this is my itinerary: Zurich airport-Thun day 1, Boat ride Thun-Spiez and then train Spiez-Zermatt, day 2 and then Zermatt-Chamonix day 6 and Chamonix-Zurich day 10 should I get a 3 day flexi pass and use the it as a "half fare" for Zermatt to Chamonix (can I even do this? Decide if I want to use it as a "half fare" card when I still have trips left on it?) or do I need to buy a 4 day flexi card?

Hello Lisa. Both a 3 day Swiss Saver Flexi Pass (using a discounted day for Zermatt-Chamonix) and a 4 day Swiss Saver Flexi Pass (using a free travel day for Zermatt-Chamonix) would work. You can decide which variant you think is most economical or most convenient for your itinerary. Zermatt-Chamonix is quite a long and expensive trip, so I think a 4 day Swiss Saver Flexi Pass is convenient.

Did you check the Swiss Flexi Pass page? It's explained how the pass works there. You can spread 3, 4, 5 or 6 free travel days over a period of one month max. On such a free travel day, you can make all the trips you want. The downloadable validity map shows where free traveling is allowed on such days. On all other days in between your first and last free travel day, discounted traveling applies.

I read in your other post that you're still looking for hotels. Our lists of hotels close to railway stations (including Zermatt, Zurich and Zurich Airport) may be of help.

I hope it's clear now. Best regards,