Editing Back-of-the-envelope calculation (section)

{{Short description|Metaphor for a rough calculation}}
A '''back-of-the-envelope calculation''' is a rough calculation, typically jotted down on any available scrap of paper such as an [[envelope]]. It is more than a [[guess]] but less than an accurate [[calculation]] or [[mathematical proof]]. The defining characteristic of back-of-the-envelope calculations is the use of simplified assumptions.

A similar phrase in the U.S. is "back of a [[napkin]]", also used in the business world to describe sketching out a quick, rough idea of a business or product.<ref name="brown2011">{{Cite web|last=Brown|first=Bob|date=2011-07-19|title=Napkins: Where Ethernet, Compaq and Facebook's cool data center got their starts|url=https://www.networkworld.com/article/2220218/napkins--where-ethernet--compaq-and-facebook-s-cool-data-center-got-their-starts.html|access-date=2020-10-06|archive-url=https://web.archive.org/web/20190815005607/https://www.networkworld.com/article/2220218/napkins--where-ethernet--compaq-and-facebook-s-cool-data-center-got-their-starts.html|archive-date=15 August 2019|url-status=live|publisher=[[International Data Group|Network World]]|language=en|quote=[[Robert Metcalfe]]'s early [[Ethernet]] diagrams from his days at Xerox PARC back in the early 1970s might be the most famous napkin sketches in the technology industry.}}</ref> In British English, a similar [[idiom]] is "back of a [[cigarette pack|fag packet]]".