How many days in Venice?

3 nights (2 and 1/2 days) is more than adequate, also including a visit to the lagoon islands of Murano (Venetian glass factories) and Burano (colorful facades).

also the Lido is just a vaporetto ride away. There are great beaches and elegant hotels. It's closer than Murano!

We spent four nights (3.5 days) last August and thought it was perfect for a first visit. We spent one day visiting the islands. Some of our party visited Lido beach a different day.

I had a week there (7 nights/8 days, arriving mid morning and departing in the evening) which was a bit too long as there’s a limit to how many dark paintings in cold churches you can see in one trip.

We went to Murano, Burano and my favourite was Torcello on separate days as half day trips plus an afternoon at Lido, which is very different. Five days would have been a better length of trip. We went in January when there were no queues.

Three to four full days at a minimum. One visit we stayed two weeks and did day trips too.

This is all so helpful, thank you!

We spent a week in Venice in 2018. We felt it was perfect. We were doing ancestral research and didn’t want to leave. We enjoyed walking off the beaten path, visiting Burano & Torcello on the same day. We enjoyed a couple hours on the island of San Giorgio Maggiore another morning. A nice view from the bell tower of the Basilica towards Saint Mark’s Square. In addition if you are interested in beach time I would suggest Lido. We were there for the Venice film Festival, admiring the Art Deco architecture, strolling Viale Santa Maria Elisabetta and searching for ancestors at the Venetian cemetery, founded in 1386. Can hardly wait to return to Venice.
Edited to add: https://theculturetrip.com/europe/italy/articles/the-top-10-things-to-do-and-see-in-lido-venice/?amp=1

I did one full day on my first trip. The second ( 48 years later ! ) was 3 days. I think 2 full days is sufficient, depending on what else you are doing on your trip.

It depends on what indoor sights you want to see and at what depth. I'd want at least two days just walking around outside (but I realize I'm strange), at least one day for the out-islands, and then extra time for San Marco, the Guggenheim, the Accademia, and other art museums. Then you have the churches. And (for me) the glass shops.

I believe those with no interest in churches beyond San Marco, museums, Murano, Burano or Torcello could manage with two full days. That would be enough time to cover San Marco and the Rialto Market, a vaporetto through the Grand Canal, and some wandering-around time.

Two full days (three nights) absolute minimum, three or four would be better. Keep the teens stoked on gelato and they'll follow you anywhere! ;-)

Our first visit was for six nights.
Two years later we returned, and stayed for two months.

Depends what grabs you, I suppose.