In Back to the Future, when Marty is stuck in the past, he visits a known diner from his timeline and asks the server about the phone booth and the address of Doc Brown. The server angrily asks him "if he's going to order something", to which Marty asks for a "Pepsi free" and the server replies "If you wanna Pepsi, you're gonna pay for it."

Why and how was Pepsi free in Marty's own time (i.e. 1985)?

Was Pepsi free during that time in the real-life USA?

  • Comments are not for extended discussion; this conversation has been moved to chat.
    – Napoleon Wilson
    Commented Nov 30, 2021 at 19:10

1 Answer 1


"Pepsi Free" was a caffeine-free version of Pepsi introduced in 1982. This product would have been familiar to Marty in 1985, but unknown to a soda jerk in 1955, hence the joke.

In 1987, after the movie was released, Pepsi phased out the use of the name "Pepsi Free". It is now known more descriptively as "Caffeine-Free Pepsi".

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(From r/vintageads)

In addition, a can of diet Pepsi Free can be seen next to Marty's clock radio in 1985.

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Note that scene linked in the OP also has some wordplay on the word "tab", which can mean a running bill at a restaurant or bar but was also a sugar free soft drink introduced in 1963 (and is still around today).

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Again, the scene plays on the differences between a word's meanings in 1955 versus 1985.

  • Comments are not for extended discussion; this conversation has been moved to chat.
    – A J
    Commented Dec 2, 2021 at 3:48
  • Update: Tab was discontinued in 2020. The Tab that may be available in stores is soda made and packaged before it was discontinued that hasn’t yet been sold and consumed. Commented Feb 6, 2022 at 18:47

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