Project Hail Mary can mean either the book or the upcoming movie , so here’s both:

How long is Project Hail Mary (movie)?

Recent studio and director confirmations put the official runtime at about 2 hours and 36 minutes (156 minutes), including credits. Early cinema listings briefly showed a longer cut (around 2 hours 46 minutes), which caused confusion, but that has since been corrected by PR reps and the filmmakers.

Quick movie facts

  • Official runtime: ~156 minutes / 2h 36m.
  • Conflicting early listings: up to 166 minutes / 2h 46m , now walked back.
  • Release window: reviews dated March 2026 discuss the theatrical opening around March 20, 2026.

So if you’re planning a theater trip, you’re in for a fairly long, epic- style sci‑fi session, closer to Dune: Part Two than a brisk 90‑minute movie.

How long is Project Hail Mary (book)?

If you meant the novel by Andy Weir :

  • Print length: about 496 pages in common editions.
  • Estimated word count: roughly 124,000 words.
  • Estimated reading time at ~250 words/min: about 8 hours 16 minutes of actual reading.

Reading-time breakdown

  • Fast reader (300–350 wpm): roughly 6–7 hours total. (Derived from the 124k word estimate and typical reading speeds.)
  • Average reader (around 250 wpm): ~8+ hours.
  • Casual pace, ~30 minutes per day: about 17 days to finish.

The book mixes conversational storytelling with real science, so most people find it quick-moving but occasionally slow down on the more technical bits.

Mini comparison table

[1][3][5] [2][9]
Version “How long” Details
Movie ~2h 36m
Book ~8h 16m to read Approx. 124,000 words; ~496 pages; based on 250 wpm average reading speed.

If you’re deciding what to do tonight

  • Want a single sitting experience: the movie’s 2.5+ hours is a solid night out.
  • Up for a multi-day immersion : the book can comfortably fill a week or two of evening reading.

TL;DR:

  • Movie: about 2 hours 36 minutes.
  • Book: about 8 hours of reading for an average reader.

Information gathered from public forums or data available on the internet and portrayed here.