/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

14,865 Subscribers

3

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

2 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

6

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

9

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

3

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

6

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

1

Construction Estimators

Construction Estimators, are any of you in here flying solo? If so can you elaborate on the process you took? I.e how did you set up your payment structure, is it hourly? Or per estimate? Advertising, etc. If you don't mind. Background on me, I've been working for a remodeling contractor for 2 years after working in the field for 20 years before that. I've created a great staple pricing database. I've been surpassing my profit margins so I'm looking to maybe fly solo and thought I would maybe start offering third party estimations or something along those lines.

1 Comment
2024/08/02
22:14 UTC

1

Estimating Business - NSW Australia

Hi all,

Just wondering if it's worth starting a estimating business, that does take-offs/costings for head contracting commercial companies.

The market in Australia NSW atm seems abit slowed down, but do companies generally outsource any estimating or an in need of a estimator for head-contracting works (i.e public school refurbishment,office fit outs?

What are your thoughts on this?

1 Comment
2024/08/02
03:01 UTC

0

reddit account buy

I was wondering if any one want to sell his rdt account ?
I’d definitely pay you for it!

Let me know if any one interested.

Thanks!

6 Comments
2024/07/30
17:58 UTC

4

If Jupiter were condensed to liquid, how large would it be, relative to Earth?

Chatgpt told me it would be roughly 1.3x Earth but with lots of caveats and I just can't trust it.

Seems small...?

4 Comments
2024/07/29
20:06 UTC

3

How many sandwiches exist in the world at one time?

Assume that once a bite is taken, the sandwich ceases to exist. Hamburgers and hot dogs don't count. Wraps and gyros do count.

6 Comments
2024/07/29
12:15 UTC

5

What are the chances of having ANY known disorder/disease with frequency at most 1 in a million?

Whenever somebody has a condition with a frequency of less than 1 in a million, we freak out because 1 in a million is like winning the lottery.

But really, the chances of having a condition of frequency less than 1 in a million, has to be much higher than 1 in a million chances. So how likely is it?

2 Comments
2024/07/28
18:47 UTC

1

[Request] Maximum possible number of Earth area space dwellers?

So I've been a bit bored, and like any good writer, I decided to dig far too deep into a topic, in this case, space colonization.

So, I wonder what the hypothetical maximum population of the "earth area" could be, that being the Earth, the Moon, and all of the Earth-Moon Lagrange Points.

So, to start with, I think that the most reasonable types of hypothetical space colonies are the Stanford Torus, which has a hypothetical maximum population capacity of around 140,000 people, the Bernal Sphere, which could have a population of about 30,000 people max, and the O'Neill Cylinder, which O'Neil stated could house around 10 million people maximum, but this is debated somewhat. Feel free to use the 10 million figure if you wish, for the sake of simplicity. There are five Lagrange Points in the Earth-Moon system. Here is where I need the math help. I'm not entirely sure how big a Lagrange point is. How many of each type of colony could hypothetically fit inside of one Lagrange point? Could you also set up smaller binary systems of "groups" of colonies at each Lagrange point to increase the number of colonies? Also, O'Neil Cylinders need to have an even number in a group to function properly, so if you're using them for your population figure math, keep that in mind.

Then there's also the moon. I've seen various figures online. Some of them rely on the average area needed for a human being, reaching about 3.8 billion, while another one using different population density metrics, has gotten over a trillion. Feel free to use whatever metric you want, but I think that 3.8 billion is probably the most reasonable.

There also hypothetically could be habitats kept in geosynchronous orbit, but for now, let's leave off those.

Sorry if this is not the proper place for such a silly question.

1 Comment
2024/07/27
01:16 UTC

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