Fear is subjective, which makes ranking the scariest movies of all time a tricky task. The folks at GIGACalculator.com are all about numbers, and they've found a way to translate a film's fear factor into hard data. Based on their findings, these are the horror movies most likely to get viewers' hearts racing.

To compile their list of the most terrifying horror flicks, GIGACalculator.com showed movies to 150 first-time viewers while tracking their heart rates. The film selection was determined by a survey of 2500 self-proclaimed horror fanatics prior to the study.

Director Ari Aster's 2018 movie Hereditary took the top spot with pulses rising to an average of 115 beats per minutes (BPM) during viewings. For comparison: A healthy average resting heart rate falls between 60 and 100 BPM. Taking the number 2 spot was the 2004 gore-fest Saw, which jacked up heart rates to an average of 113 BPM. The Babadook (2014), Insidious (2010), and A Quiet Place (2018) rounded out the top five. You can see the full ranking below.

As horror fans know, a movie that raises your heart rate in the moment won't necessarily give you nightmares days later. For another perspective on the best scary movies, check out the favorite horror films of famous directors in the genre.

  1. Hereditary (2018)
  2. Saw (2004)
  3. The Babadook (2014)
  4. Insidious (2010)
  5. A Quiet Place (2018)
  6. The Descent (2005)
  7. Us (2019)
  8. It (2017)
  9. The Conjuring 2 (2016)
  10. The Exorcist (1973)