/r/estimation

Photograph via snooOG

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.

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 m3

  • Muzzle velocity of a round fired from a 9 mm Glock 17: 375 m/s or 1,350 km/h


Estimation strategies:


Other related subreddits:

/r/estimation

14,876 Subscribers

2

How many ancestors does one have going back 10 generations?

So if I consider my parents the first generation and absolutely no one in my family ever married anyone even remotely related to them, I would have 1024 ancestors in the 18th century.
However, for much of the time since then, people lived in much smaller communities with much less (social mobility) and a higher acceptance to marry distant cousins so chances are that there were marriages between people sharing the same ancestors.
In other words in the family tree with 1024 entries, how many of them show up twice because my grandmother and my grandfather had the same great great grandfather for example?

0 Comments
2024/12/03
10:47 UTC

0

The ultimate question

The very existence of this question is an official brain breaker if you aren’t a person with enough time to truly think about it the question is and I quote “ would you rather have unlimited bacon but no games, or games, unlimited games, but no games.” The question itself is well built and though I can only type this message the answer is based on how it’s said the answer to be chosen is number two it’s kinda like combining like terms but with words you have two games and one unlimited games when you combine like terms one cancels out the other leaving unlimited games (better) however bacon but no games being simple but loss of benefit therefore with more possibilities and simply a better option games, unlimited games, but no games wins hope that clears it up

0 Comments
2024/11/28
09:53 UTC

2

[Request] Assume I have a pound of flesh and, through some means, manage to break every single covalent bond in it, leaving me with a pound of assorted mono-atomar carbon, nitrogen, oxygen etc. What kind of ballpark is the ensuing BOOM in when the atoms inevitably recombine?

0 Comments
2024/11/27
16:38 UTC

0

[ Removed by Reddit ]

[ Removed by Reddit on account of violating the content policy. ]

2 Comments
2024/11/11
21:01 UTC

0

How come my gf 5'8 , 85kg is stronger than me 5'4 , 56kg?

Hi I always thought doing running and athletic gains strength. But my gf who is 4 inches taller and 30 kg heavier is stronger than me. She barely worksout .

She has big arms and upper body along with big thighs which are firm .

I tried armwrestling her, she smiled winked and defeated me . I tried lifting her i couldnt but she could with one hand. I was having shock face and she was smirking the whole time.

We tried wrestling and she sat on my chest i tapped out. When i sat on her she casually slammed me on the side. This is leading to a situation where she winks and physically dominates me.

Like when i was studying she came in the room and said hey short handsome and then bear hug me suffocating my face in her belly and laughed while pushing me making me fall to the ground

in general a boy is stronger than girl.

have u faced this or know somethijng like this.

who would win in this scenarior

11 Comments
2024/11/09
03:38 UTC

0

Could a 5'6 , 80kg girl beat a 5'4 , 56kg guy in wrestling? Ever saw it?

I am 5 foot 4 ,56kg

Girls in my class of 5'6 , 85kg have challenged me to wrestling .

I am confident i will win as size doesnt matter. I am faster than them.

what do u think what will happen with me?

Ever saw a big girl take down or defeat a small guy?

8 Comments
2024/11/02
16:21 UTC

2

How to tell how loud something is without a measurement tool?

I want to figure out how loud my car engine is without using any tools like a dB reader.

8 Comments
2024/10/19
21:19 UTC

7

How heavy (in kilograms) could I make a two-litre bottle by filling it with sand and then adding as much water as would fit in between the sand particles?

Assume it is sharp sand from a DIY store.

4 Comments
2024/10/18
20:33 UTC

0

In theory if a human got swept up by wind and carried through the air how fast could they potentially go

3 Comments
2024/10/11
20:43 UTC

0

How can somebody reach out to vendors for pricing?

Hey guys! I recently started my own business offering estimation services for low-voltage projects. Some of my first clients are quite new to the industry and don’t have established vendor relationships to get accurate material quotes. I find it frustrating to create estimates for bids with a low chance of success due to this issue. I’ve been exploring ways to reach out to local vendors or vendors like Anixter, Graybar, and Accu-Tech across different locations to secure the best and most competitive quotes.I have been operating remotely so If anyone has insights or can point me in the right direction, I’d greatly appreciate it. Thanks!

1 Comment
2024/10/07
16:00 UTC

1

How long, if ever, until a mars colony with more or less permanent residents?

As in people that plan to stay there most of their life, maybe go back to earth after retiring or something.

Bonus question because the above is largely speculation, how much is the total biomass of all ants on earth?

8 Comments
2024/09/29
08:30 UTC

7

What percentage of the world's population has never ridden in an elevator?

8 Comments
2024/09/28
17:06 UTC

9

If we closed Everest and kept anyone from climbing it, about how long would it take for all the trash on it to "naturally" erode away?

5 Comments
2024/09/24
19:17 UTC

10

If the entire land mass of Earth was to be reshaped into a perfect sphere, how tall/deep would the resulting water level be afterwards?

Like if all the water on Earth is temporarily removed and Earth is reshaped into a perfect sphere and then put the water back again, how tall/deep would it be

15 Comments
2024/09/17
15:17 UTC

5

Worldwide, are there more: People who don't eat beef, people who don't eat pork, or people who don't eat any meat at all?

Occurred to me last night and I guess my gut response is that "people who don't eat pork" is the biggest group, but I'm curious about the hivemind's take.

5 Comments
2024/09/12
22:12 UTC

3

How large are the nuclear weapons used in the Fallout Series?

I've been having a discussion with a friend and he doesn't think they're very big. You can see them in this YT clip for reference.

https://www.youtube.com/watch?v=Gq7cGlGCla8

At the end the one being dropped looks like it hits Hollywood based on the reference point of Griffith Observatory.

I tried to use the nukemap to try and estimate it but I'd like to see if anyone else has a method of approximating it.

Nukemap for reference - https://nuclearsecrecy.com/nukemap/

2 Comments
2024/09/12
08:50 UTC

0

A perfect sphere has infinite sides, but no man-made or natural object is a perfect sphere. With that, how many sides does a ping-pong ball have?

Clarity in comments

13 Comments
2024/09/01
18:06 UTC

2

Physics fermi problem

What weight of trash will a typical American generate in a lifetime?

I’m struggling with just coming up with the assumptions, I know the conversions.

But if I know the average lifespan is 78

My assumption couldn’t be how much trash per day an average American weighs right?

Cause then I’d literally only have to multiply it by their lifespan so I feel like I’m oversimplying it

1 Comment
2024/08/27
23:13 UTC

5

How powerful would an impact of an asteroid be if it was the size of Texas?

Tried asking this on r/askscience but it got deleted so I'll post it here

So in Invincible, Mark stopped an asteroid from hitting Earth and then Omni Man tells him that was a "small one" and claimed to have stopped an asteroid as big as Texas. But just how powerful would the impact be of an asteroid as big as Nolan claimed?

17 Comments
2024/08/19
12:01 UTC

17

if two tennis balls are placed 1 mile apart in a vacuum with no other forces, how long would it take for their gravity to collide them?

7 Comments
2024/08/08
21:26 UTC

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