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Comment by boomboomsubban | Hacker News Reader

How often are you converting miles to feet?

Giving road directions, especially if you are sitting in the passenger seat navigating for someone, is an example that comes up in my life fairly frequently. It gets awkward to talk about things that are between 0 to 1/2 mile so I find myself trying to do the mental math to convert to feet for someone else. These days I usually give verbal directions in meters. Most people in the United States seem to have some conceptualization of what a meter is so it usually works quite well as it’s also easier for me to estimate meters instead of feet.

>Most people in the United States seem to have some conceptualization of what a meter is so it usually works quite well as it’s also easier for me to estimate meters instead of feet.

I think most people in the US just convert the meter to the three-foot yard measure. I doubt people would notice if you did the same thing in order to give estimates in feet. I work in metric weights but speak to people using US Imperial weights, so I regularly say something is "about 4 ounces," and the same idea of something being "about 1000 feet" would likely be fine since you're already estimating.

Given that road directions aren't even remotely precise, it's fine to just consider a mile to be 5000 feet, and if you want to say "a quarter mile" you can just say 1250 feet. Or even 1500 feet if you want something more round. Most people will not meaningfully feel the difference between "turn right after 1250 feet" and "turn right after 1500 feet" when moving at car speeds.

When I'm cycling I'm comparing metres to kilometres all the time; in imperial you'd presumably have to do the same with feet to miles (or maybe yards, but they seem to be a more obscure measurement - e.g. people talk about speed in feet per second but not in yards per second).

In imperial/US (which are not identical) you simply think of it differently, using a quarter mile, half mile etc. Using rational fractions (1/2, 1/3, 1/4 ... 11/16 etc) are very simple and natural in that system. Having lived in countries that use on or the other, or have transitioned (and having been born before currency decimalization) I appreciate the strengths and weaknesses of both systems, and use each in its “natural” mode, just as I don’t speak a second language using the grammar of the first.

Metric is not “automatic” either. One year in university I took three classes that happened to be in the same classroom. One was in cgs, one was in MKs and one in ASME units (US customary units plus mils). Three different subject domains. It didn’t feel odd or complicated.

Never since I'm not American, but if I were I'd use a calculator. I think this is primarily bad for kids who have to do miles to feet conversion in math problems. It could even be lowering math scores, who knows.

My local swimming pool is two hundred feet long

Never. But meters to kilometres all the time.

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