The super-slow conversion of the U.S. to metric (2025) • Hacker News Board

Re: The super-slow conversion of the U.S. to metric (2025)

#251

Post by bigstrat2003 » Wed, Jan 21, 2026, 5:50 PM UTC

People get bogged down in arguments about what's better or more natural, but in my opinion those always miss the point. The truth is, there's no incentive for the US to switch. If you're a typical adult living in the US, you already know all the conversions you will need (12 inches to a foot, etc etc). The math isn't hard, because you always have a calculator at hand in this age. In short, imperial units have zero downside for most people. On the other hand, switching units of measurement does have a major downside as you have to relearn to estimate everything in the new units. That would be fine if metric was solving a problem for you... but it's not, so why switch?

The only people who benefit from a switch to metric are kids (cause they won't have to learn the imperial conversions). And they, for better or for worse, don't get a say. If people really want the US to switch measurements so badly (which I have no idea why anyone gives a shit what our country does, it's not like it affects them), then they need to come up with an actual compelling benefit to adults in the US if they switch. 100 years ago there was one: you can do conversions more easily. But today there is not, and until one surfaces there's going to be zero pressure to switch units.

Re: The super-slow conversion of the U.S. to metric (2025)

#252

Post by ericmay » Wed, Jan 21, 2026, 5:50 PM UTC

nearbuy wrote: post #216

ericmay wrote: post #166

Earlier quoted context omitted.

Well even 0-96 would be better, but I think 0-100 scales are more useful. Temperatures in most places are within those bounds and it's like a test you are graded on. You get a 0 on the test, that's really cold. You get a 100 - smoking hot. I'm not 100% sure of the normal upper/lower bounds in everyday life for most people on the planet for Celsius, but let's say it's 0-32. It' just feels weird to me to be operating o…

I think you're saying that where you live, the weather is usually between 0 and 100°F. Aside from the fact that outdoor temperatures aren't in this range everywhere, we don't only use temperature for weather. 100°F is warm to the touch, not smoking hot. 100°C is boiling hot. You sip tea at 60°C, and brew it at 80° to 100°C depending on the type. You cook chicken to an internal 74°C. A hair dryer blows air around 50°C…

> I think you're saying that where you live, the weather is usually between 0 and 100°F.

Well let me clarify, what I was saying is that where everybody lives the temperatures tend to be within that range, which is why I think it's a superior measurement for temperature related to the weather - again just additional clarification which was missing maybe from earlier comments.

Once you arrive at the point where you're measuring various things, I'm not sure it matters what scale you use so long as the values align as you expect. In other words, I don't really care whether I'm using 212 for the temperature at which water boils or 100 - it's just an association of values to action. You can swap between grams, ounces, pounds, milligrams, or kilos with your scale and it's not that important for day-to-day life. In terms of measuring temperature of things, like, say when chicken is cooked, I'm not really sure F or C is more practical. It's just different numbers.

Re: The super-slow conversion of the U.S. to metric (2025)

#253

Post by prmph » Wed, Jan 21, 2026, 5:50 PM UTC

beloch wrote: post #242

To those who cling to customary units because... 1. "They're more intuitive". They're not. You're just familiar with what 70 F feels like. If you're used to metric, 70 F is meaningless, but you intuitively know what 20 C feels like. 2. "Metric leads to lots of awkward numbers." All systems will fortuitously have round numbers in some contexts and awkward numbers in others. Customary units are different in that there…

Yeah, those people should also think about the fact that even the customary units die-hard do not use micro-feet, milli-feet, or nano-feet, etc.

Re: The super-slow conversion of the U.S. to metric (2025)

#254

Post by samus » Wed, Jan 21, 2026, 5:50 PM UTC

sowbug wrote: post #175

amanaplanacanal wrote: post #144

Earlier quoted context omitted.

A year and a day don't line up at all, so we get weird leap days.

Is there any reason they should? Unless the Earth were tidally locked to the Sun, I'm not aware of any reason a day would have any relationship to a year.

It would be convenient to not having to deal with leap days and other such constructs. Of course, we cannot choose how these things behave, and therefore using a calendar not aligned to the natural cycles of our planet would be even less convenient, and would only start making sense when humanity develops into an interplanetary civilization.

Re: The super-slow conversion of the U.S. to metric (2025)

#255

Post by zzzoom » Wed, Jan 21, 2026, 5:51 PM UTC

gordonhart wrote: post #129

threemux wrote: post #62

I'd part with cups and teaspoons/tablespoons and the like, but you'll pry inches/feet/yards and fahrenheit from my cold, dead hands. They're both more convenient for daily use. I think I'd prefer to keep miles as well but I don't have a good reason for that one. Fahrenheit has more precision without using decimals for the thing 99% of people are using temperature measurements for: air temp. Where I live, we generally…

Miles didn't click for me until I learned that it's defined by how far you'll travel in 1,000 paces (where a pace is an L+R step). Now I find it very useful to convert steps distance traveled, which is actually quite useful if you walk a lot!

You'd have to be quite tall to average an ~80cm step. 193cm (6'4") according to a quick search.

Re: The super-slow conversion of the U.S. to metric (2025)

#256

Post by bigstrat2003 » Wed, Jan 21, 2026, 5:52 PM UTC

beloch wrote: post #242

To those who cling to customary units because... 1. "They're more intuitive". They're not. You're just familiar with what 70 F feels like. If you're used to metric, 70 F is meaningless, but you intuitively know what 20 C feels like. 2. "Metric leads to lots of awkward numbers." All systems will fortuitously have round numbers in some contexts and awkward numbers in others. Customary units are different in that there…

> You're already using metric units.

No we aren't. It doesn't matter what the units are defined as, that is not what determines which units we are using.

Re: The super-slow conversion of the U.S. to metric (2025)

#257

Post by samus » Wed, Jan 21, 2026, 5:53 PM UTC

Kim_Bruning wrote: post #87

threemux wrote: post #62

I'd part with cups and teaspoons/tablespoons and the like, but you'll pry inches/feet/yards and fahrenheit from my cold, dead hands. They're both more convenient for daily use. I think I'd prefer to keep miles as well but I don't have a good reason for that one. Fahrenheit has more precision without using decimals for the thing 99% of people are using temperature measurements for: air temp. Where I live, we generally…

An eyeballed yard is roughly the same as an eyeballed meter. An eyeballed foot is 1/3 of that. You can stick 4 inches in 10 cm roughly. And I just poke my nose out the window and look outside to see what the temperature is Freezing.... ~30°F.... ~0°C Need coat... ~50°F... ~10°C T-shirt..... ~70°F... ~20°C Melting..... ~90°F... ~30°C Rules of thumb can be learned either direction! ps HN tables are not really a thing,…

The difference between a yard and a meter adds up quickly. Already a 25 yard swimming pool yields significantly different times to cross it than a 25 meter one.

Re: The super-slow conversion of the U.S. to metric (2025)

#258

Post by IAmBroom » Wed, Jan 21, 2026, 5:53 PM UTC

etiennebausson wrote: post #102

flohofwoe wrote: post #82

Earlier quoted context omitted.

> They're both more convenient for daily use. That's really just because you're used to it. The rest is rationalization... OTH of course the rest of the world can hardly complain since we didn't switch time or (angle-)degrees to decimal either ;)

Not switching to metric for time is reasonable, because there are already two existing 'natural' units for time (the day and the year), and they don't align on each other in metric (a year of exactly 1000 days would be so much easier, but we'll have to deal with reality as it is... or accelerate the rotation speed of the planet I suppose). So long as we live on earth, metric time won't make much sense.

The US isn't on a 365.24-based system, either. Days don't fit neatly into years, anyway.

That would have no impact on decimalizing sub-day units: 10 decidays in a day, 2 millidays to cook an egg... But no country did it, which speaks to the power our time traditions really hold in our psyche.

Re: The super-slow conversion of the U.S. to metric (2025)

#259

Post by SECProto » Wed, Jan 21, 2026, 5:53 PM UTC

candiddevmike wrote: post #132

jlongman wrote: post #79

Earlier quoted context omitted.

That’s funny because when I work with Fahrenheit I just work with 5°F ranges to compensate for the approximate mental math required. Eg very quick mentally, 100°F = 37.778 °C (thanks autocorrect) = (100-32)/2 = 34. But if it was closer to freezing say 42°F =5.556 °C (again) so 5°C. So arbitrarily we could say 57°F was 12°C =53.6 °F actually. But a true Canuck knows knowing the temp is barely half the battle, what’s t…

(F - 30) / 2 = ~C C * 2 + 30 = ~F

No need to simplify this.

(F - 32) / 1.8 = C

C * 1.8 + 32 = F

I personally find the math just as easy to do accurately. For example, 87F -32/1.8 = 55/1.8 =~30.5C. Compare that to your approximate method, which would give 28.5C, which is just wrong

(Maybe I just got really good at this when working a public facing job with a lot of American tourists - they would ask what our celsius temperatures were "in real units", so I got quite comfortable converting the air and water temps. Fahrenheit never once became intuitive to me, though.)

Re: The super-slow conversion of the U.S. to metric (2025)

#260

Post by upofadown » Wed, Jan 21, 2026, 5:53 PM UTC

>“I’m currently working on a mounting plate that’s 4.5 by 8 in. that needs a 40 mm bore 1/2 -in. deep located 75 mm from the edge with m10 tapped holes and two 1/4-20 set screws tangential to the bore. Please kill me.”

When I was designing stuff here in Canada, that was basically Wednesday. One big advantage of the USA withdrawing from trade is that Canada will have the opportunity to finally complete the metric conversion.