r/estimation

4.1K archived posts · Jul 2012 – Sep 2026

Estimation

r/estimation

Ever wondered what the rate of gummi bear combustion needed to power a lawn mower is? How fast do you need to throw a burrito to make it spontaneously ignite? A subreddit dedicated to one of the most useful skills in life. Estimation.

Created Jul 9, 2012

15KMembers (last snapshot)

4.1KArchived posts

This subreddit is dedicated to taking a stab at answering hypothetical, interesting and often untestable questions. In reality, you're never going to get a perfect answer. Some things just can't be tested. That's why estimation is such a valuable skill.

The following types of posts are allowed:

Links to reddit posts related to estimation. Please include the actual estimation in the post title. Example
Requests for estimations as long as they have the [Request] tag in the title. Self posts are preferred. Example
Links to websites related to estimation.

When fulfilling requests

List all assumptions made
Link to sources wherever possible
Use SI units for your final answer
Don't downvote because someone's answer is different. As long as they have made appropriate assumptions and done their calculations correctly, their answer is valid.

Reference dimensions

Wolfram Alpha (Mobile version doesn't have ads)
Length of an everyday car: 4.4 m
Weight of an everyday car: 1300 kg
Length of a football field: 100 m
Volume of an Olympic swimming pool: 2,500 m^3
Muzzle velocity of a round fired from a 9 mm Glock 17: 375 m/s or 1,350 km/h

Estimation strategies:

Fermi estimates

Other related subreddits:

Other communities

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