What were Mike, Robbie and Chip's ages when My Three Sons debuted in 1960?

They have said Chip is in the third grade, so he would be 8 or 9.

Mike is checking colleges (State, of course!) so he is probably a senior, around 18.

I think in season 6 Robbie is starting college, so if it's running right, he would be in the 8th grade, around 13. He really looks older than that, though.

I guessed Chip at about 8 because they mention the 3rd grade and Mike at 17-18 because he was a senior. I haven't heard a grade given for Robbie. I guessed he was about 13-14. The reason he looked older is because Don Grady had turned 16 in June, 1960. Thanks!

In today's 1st episode Steve said Robbie was 15. So he may have been 14 at the start.

I think in season 6 Robbie is starting college, so if it's running right, he would be in the 8th grade, around 13. He really looks older than that, though.

I don't believe Rob has started high school, so 8th grade is appropriate -- but he could be 14, as many in that grade turn 14 prior to starting high school.

I don't believe Rob has started high school, so 8th grade is appropriate -- but he could be 14, as many in that grade turn 14 prior to starting high school.
In one of the first episodes, the one where Robbie accuses Mike of "stealing" his girlfriend, in the scene where the girl mistakes Robbie for Mike, Mike is at school with his brother, so it's likely that Robbie is in high school.

I'm familiar with that episode -- but Robbie is with the junior high group. As with some school systems, the junior high shares property with Bryant Park High School, where Mike attends.

Edit: Just wanted to add that in one of the episodes aired on Mon., June 19 on MeTV, Robbie goes into the music room with a handwritten notice on the door for "JUNIOR HIGH BAND PRACTICE." How is that for evidence?

Does Chip have a given name other then Chip?

Richard. I guess "dick" would have been to clunky.

They never explained where "Chip" came from (that I'm aware of). Maybe Robbie tried to say Rich when he was small and it came out Chip.