Why did Doctor Strange give the time Stone to Thanos?

During the final act of Avengers Infinity War, Iron Man was about to be killed by Thanos on Titan. However, Doctor Strange willingly gave up the Time Stone to spare Tony Stark’s life. As a result, Thanos managed to collect all six Infinity Stones and snap away half the universe, including the Sorcerer Supreme himself.

Why did Doctor Strange ask Tony Stark to open the portal?

Remember, Strange was tortured by Ebony Maw and during the short fight where they eject Maw into space, Strange was completely helpless. Maybe Strange wasn’t strong enough to open the portal to Earth and that’s why he asked if Tony could do it. – Shreedhar

Did Doctor Strange ever try to use the time stone?

The most obvious comes from those 14 million futures Doctor Strange saw; it’s entirely possible that he did attempt to use the Time Stone in one or more of them, only for it to not succeed in ultimately stopping Thanos. Indeed, Dormammu was from the Dark Dimension, an alternate world that is removed from any conventional understanding of time.

How did Doctor Strange know they were going to Titan?

The clearer the picture, the quicker, and easier, the gateway will come. We know that Strange knows Earth and as an Earthling he can visualize places on Earth. But during that scene where he asks Tony Stark if he can control the ship, he knows they are going somewhere which is not The Earth. They were going to Titan.

What exactly was Doctor Strange doing in Infinity War?

Admittedly, there is a lot of debate over what exactly Doctor Strange was doing in Infinity War – after seeing 14,000,605 futures, he decided to give Thanos the Time Stone, enabling him to ultimately kill half the universe – but this one aspect seems a cut-and-dry oversight. Even Thanos himself questions it during their fight.