# Weight of a fart

**URL:** <https://boards.straightdope.com/t/weight-of-a-fart/5364>\
**Category:** Factual Questions\
**Created:** [December 16, 1999, 2:05am UTC](https://boards.straightdope.com/t/weight-of-a-fart/5364 "1999-12-16T02:05:00Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Paul\_Rosen](https://avatars.discourse-cdn.com/v4/letter/p/f14d63/32.png) [@Paul\_Rosen](https://boards.straightdope.com/u/Paul_Rosen)\
**Post date:** [December 16, 1999, 2:05am UTC](https://boards.straightdope.com/t/weight-of-a-fart/5364/1 "1999-12-16T02:05:00Z")

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Is a person lighter, heavier, or the same weight after they fart? Does it matter if the person is in Denver or Death Valley?

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**Author:** ![Arnold\_Winkelried](https://avatars.discourse-cdn.com/v4/letter/a/3d9bf3/32.png) [@Arnold\_Winkelried](https://boards.straightdope.com/u/Arnold_Winkelried)\
**Post date:** [December 16, 1999, 2:14am UTC](https://boards.straightdope.com/t/weight-of-a-fart/5364/2 "1999-12-16T02:14:00Z")

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Lighter. Which is why tabloids are constantly touting “flatulence diets.” Those are more or less effective. You’re better sticking with “eat more fruits/vegetables and exerice.”

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Quand les talons claquent, l’esprit se vide.  
Maréchal Lyautey

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**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\
**Post date:** [December 16, 1999, 2:21am UTC](https://boards.straightdope.com/t/weight-of-a-fart/5364/3 "1999-12-16T02:21:00Z")

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Hmm… Flatulance contains methane and probably some air, so it is slightly lighter than air. So if it’s under one atmosphere pressure, having it inside your body gives you some lift, and getting rid of it makes you heavier. I’m not too sure if it IS at one atmosphere, but I’d guess it’s pretty close.

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**Author:** ![Rysdad](https://avatars.discourse-cdn.com/v4/letter/r/7cd45c/32.png) [@Rysdad](https://boards.straightdope.com/u/Rysdad)\
**Post date:** [December 16, 1999, 2:29am UTC](https://boards.straightdope.com/t/weight-of-a-fart/5364/4 "1999-12-16T02:29:00Z")

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Interesting. You would lose mass, which should make you lighter, but if the mass you lost was bouyant, the loss then would make you heavier.

My guess is, overall, you’d get lighter by a fraction.