We know they have at least one printer on the ISS – that's NASA-supplied so it would be in the US Orbital Segment. Presumably there is a printer in the Russian Orbital Segment as well. (Mir had a teletype.)

My question is – what paper size do they use on the ISS – A4, US Letter, or a mix? I assume that if Roscosmos has a printer they'd want to load it with A4; but would NASA use A4 in their printer so the whole of ISS uses a standard paper size? Or would they stick to US Letter since that's what NASA is used to?

(Also, I guess there is some argument that something called the "International Space Station" ought to prefer the international standard paper size.)

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    $\begingroup$ different but related: Was this printer shown the ISS in 2015 built specially to work in microgravity? $\endgroup$
    – uhoh
    Commented Mar 25, 2021 at 13:24
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    $\begingroup$ I like this question, but I can't help but wonder - what motivated you to ask it? $\endgroup$
    – SF.
    Commented Mar 25, 2021 at 14:29
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    $\begingroup$ They use it to print out procedures, which on the ground are US letter, but I can't find anything to confirm that's what is used up there. Cool question! $\endgroup$ Commented Mar 25, 2021 at 19:20
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    $\begingroup$ IMO, a useful answer will primarily address the physical paper sizes available on the ISS, as virtually all "modern" printers can handle a plethora of formats... $\endgroup$
    – Digger
    Commented Apr 25, 2021 at 14:33
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    $\begingroup$ @Starshipisgoforlaunch please stop making inconsequential edits to the question. "My" is fine. "So, my" isn't different (and I know for a fact that there are people who consider it incorrect). $\endgroup$
    – Erin Anne
    Commented Feb 22, 2023 at 19:33

1 Answer 1


Although one cannot exclude other paper sizes being sometimes used, US astronauts on the ISS definitely used A4 paper.

I cannot find any mention or clear images of US letter-sized paper on the ISS.

Despite being somewhat embarrassed to ask, I submitted a question to NASA about this, and several weeks later received an unhelpful boilerplate answer that just pointed me to various ISS websites.

  • $\begingroup$ Great reference! $\endgroup$ Commented Oct 11, 2023 at 16:30
  • $\begingroup$ Great source! I also found "Color Printer Paper (6 Hole, 1/4" Dia.)" on page 421, Green Record Book 8 x 10.5 lined, Metric Pad Assembly Green, Drawing Paper 14x17 white (page 453), and 8x5 inch toilet paper. I'm skeptical of IDing A4 paper instead of letter in a photo (A4 is 8.3 x 11.7 inches, versus 8.5 x 11 inch letter paper) but it is SO GOOD to have a proper answer to this question now $\endgroup$
    – Erin Anne
    Commented Oct 13, 2023 at 4:15
  • $\begingroup$ Thanks @Erin-Anne. I agree the visual identification might not be 100% certain, but I actually measured (i.e. counted pixels) the sizes. The paper in the Scott Kelly images seems clearly inconsistent with letter-sized and consistent with A4. The Shane Kimbrough paper size is more consistent with A4 than letter sized, but it isn't unambiguous since there are several overlapping and imperfectly aligned sheets on the pad. $\endgroup$ Commented Oct 13, 2023 at 14:19

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