Newcastle are currently five points above the drop zone but their rivals will have chances to bridge that gap with the 'Magpies' not playing for three weeks. Benitez though is concentrating only on what his side can control.
"I would say around 40 but maybe it could be less. I think 40 is the minimum, the guarantee to stay up," the Spaniard said to 'Sky Sports' when asked how many they would need.
He went on to talk about Newcastle's January signings, in particular Martin Dubravka and Kenedy who have both arrived on loan: "It is always important to have players competing in the same position and when they do well they push the others to do well at the same time.
"It is always a positive for the atmosphere and especially when you are winning."
Final he spoke about Jamaal Lascelles and Jonjo Shelvey being omitted from the England squad: "It is always very difficult. They were doing really well for us - that is the main thing for me.
"The manager decides his team, there a lot of players in England that can be good and then it is about his decision.
"I am happy to keep my players with this club. I told them they are still young players, they have plenty of time [ahead] so they have to keep progressing and I am sure they will have a chance.
"We have very important games in a few weeks so if they don't go [with England], they don't take any risks and it can be positive.
"But I don't say that it is right because if they go they will have the extra motivation to go with their national team.
"I am happy with the situation now and hopefully they can concentrate up to the end of the season and be crucial for us."
Newcastle next face Huddersfield after the international break and have put the time off to use by going for a four day training camp in Murcia.