People interested in this should check out Frink. It has been around for a while and has thousands of unit conversions with explanations, as well as a web interface for the unit conversions part

https://frinklang.org/ https://frinklang.org/frinkdata/units.txt https://frinklang.org/fsp/frink.fsp

It's super cool, but I'm not sure the explanation of how to calculate Fahrenheit to Kelvin is, uh, accurate. ;-) <3

"By using our Fahrenheit to Kelvin conversion tool, you know that one Fahrenheit is equivalent to 255.93 Kelvin. Hence, to convert Fahrenheit to Kelvin, we just need to multiply the number by 255.93. We are going to use very simple Fahrenheit to Kelvin conversion formula for that. Pleas see the calculation example given below."

What's the reason to use this over GNU Units?

https://www.gnu.org/software/units/

I wanted to put in a plug for my employer's open-sourced C++ units framework, called Au: https://github.com/aurora-opensource/au

The library incorporates dimensional units into the C++ type system with an emphasis on correctness (including considerations for overflow, rounding, loss of precision, etc) and minimal runtime overhead.

As a very simple example of what using this library could look like, here is a tiny code snippet taken from one of the tutorials:

  constexpr double speed_mph = 65.0;
  constexpr double speed_mps = (miles / hour)(speed_mph).in(meters / second);

  const auto time = hours(1.0)
  const auto distance = miles(65.0)
  
  const auto average_speed = distance/time;

From a user's point of view (I am a physicist by training), I find the library wonderfully unobtrusive and "natural" to use.

I got into Qalculate! last year and I haven't found any units in my day to day work as an engineer that weren't built in. Unit conversion is good but the bundling of it with more of the math equation is the ultimate usability win for me.

https://qalculate.github.io/

It should handle fractions I was trying to get the size of a quarter section. It rounds .25 to 1.

Heh, doesn't fully support the furlong-firking-forthinght system :(

https://en.wikipedia.org/wiki/FFF_system

I randomly picked "Inductance" as category, and the "units" it provides are basically a dozen or so variants of the "Henry": Attohenry, Gigahenry, Centihenry, Exahenry, Kilohenry, Nanohenry, ....

If this is how you get to "5000 units" then that feels a bit cheaty

Appreciate the effort you put into this. In terms of user flow, I typically need one or two of these use cases at a time. In that case, I just type my conversion into a search engine like Google, and often use their default box.

Can you share what types of use cases you've seen people use KodyTools for?

I didnt look but http://unitsofmeasure.org which is part of the HL7 standard for electronic medical records might be an interesting source/reference

It has zillions of base units and a algebra syntax for definitions of many more

Edit: "common" units https://github.com/ucum-org/ucum/tree/main/common-units

Has anyone found a more elegant treatment of calculating with units than the HP calculators?

I'd love to have an HP48 CLI to do unit calcs with.

  .5 * 10_m/s^2 * (15_s)^2 = 1125_m

  sqrt(6.673E-11_N*m^2/kg^2 * 5.98E24_kg / 6780_km) =
    242603.08_N^.5*m/(kg^.5*km^.5)

Everything else I've found have been just super fiddly.

Using chat gpt to build software is not good, this is not programming.

Having the units listed alphabetically rather than by size is weird. "Megabits/Minute" then "Megabits/Nanosecond" then "Megabits/Second"... ugh.

Not a big fan of having social share buttons scattered across middle of workspace, a cleaner less cluttered look is better. Good work though, looks pretty thorough as far as conversions.

So, the thing about fuel economy is that it is calculated very differently in Europe versus in the US. In Europe, they do liters per 100km, whereas in the US we measure in terms of miles per gallon.

So, mi/g => l/km requires a different kind of conversion than most of the others shown. You have to first convert mi/g to g/mi, then you can convert to l/km and then multiply by 100.

Frankly, I think the European method makes a lot more sense to me, especially as you get to higher and higher levels of efficiency. With mpg, the numbers get stupidly big when you're saving relatively small amounts of fuel. With l/km, the numbers get smaller and smaller as you increase your efficiency, and it shows you how relatively little you're actually increasing the amount of fuel saved.

What's a reason to use this over Wolfram Alpha?

It looks quite extensive, and should cover almost all practical cases.

The main limitation I see is that it seems you are limited to picking the units to convert between from predefined lists. If someone gave you say a volume specified in nmi ft^2 for instance and you wanted to convert it m^3 you'd have to do nmi to m and ft^2 to m^2 and then multiply the results to get nmi ft^2 to m^3 because nmi ft^2 is not on the volume unit list.

Those cases are probably pretty rare. It is not often that you run in to people who give you say a gasoline consumption rate of 23 picoacres or give you a cookie recipe that calls for 1.6 barn megaparsecs of vanilla. (BTW, those are 0.04 gal/mile and 1 tsp, respectively).

People always mention Frink and GNU Units, but the workhorse of desktop unit-aware calculation is, in my opinion, Qalculate. In addition to being a capable scientific calculator in its own right, its killer feature is the ability to throw 'x' anywhere into an equality, and it will solve for 'x'. AS well as making to/from unit conversion even easier this also often saves you having to rewrite physics equations to isolate the quantity of interest (and thus potentially screwing up factors when eg converting mm^2 to m^2). The composition of units + symbolic calculator is greater than the sum of its parts.

Good work. Perhaps you can steal this idea:

Metric intervention https://userscripts-mirror.org/scripts/show/130277 > Converting that old French system the Brits are still using to the metric standard of science. ~ foot, inch (00',00",00'00,00'00"), yard, mile, stone, Pound-mass/Lbs., Gallon ~ It will totally convert something heretical like: 1'23 1/4" x 2'12 5/8" into something elegant and civilized like 89.535 cm x 93.0275 cm

This (uhm) didn't take a year to make but it was rather useful when I needed it.

You could maybe use the 'units' command line program's database of conversions.

The first thing I looked for was football fields, but couldn't find it. :)

You could add GeV/c2 (giga-electronvolts per speed of light squared) as a unit of weight that is used by physicists for sub-atomic particle mass.

There is also the [units] command from UNIX. I think the original was by Ken Thompson (AFAICR).

https://www.unix.com/man-page/v7/1/units/

$ units You have: 1 foot candle You want: lumens meter * 0.310896 / 3.2165097

Good to see the completely realistic terabytes/nanosecond is included!

I'm sure messing around with that will never get old.

I cannot find a button to switch the “from” and “to” units.

IMO, any converter needs one, so add it or make it easier to find.

I have used your site before for conversion and appreciated having everything in one place. Thanks!

I think this is a great tool. Not discounting the value of work (which you started long ago) that you have done already, but I am thinking that an LLM could do it much more easily today.

Two notes: When I search for oz and ml nothing comes up. Also there should be a button to swap units like you have on xe.com (ability to swap currencies).

Many cooking utensils I have at home are either in ml or oz but not both.

As a chemical engineer, we would joke about using the worst units in problems. Had a professor specify a volumetric rate in hogsheads per fortnight for a problem once and density in stone per cubic rods

TIL that there are Tablespoons [Metric].

Also, I thought "Library of Congress" was a standard unit of measurement? Not to mention the "standard reference pear".

Looks like the site is currently blocked by Quad9 DNS.

> www.kodytools.com Server: dns9.quad9.net Address: 9.9.9.9

** dns9.quad9.net can't find www.kodytools.com: Non-existent domain

Cool site! You might consider deleting the cookie notice?

I run a similar site (dateful.com) and I promise the EU regulators don't come after sites like ours. :)

What kind of a toy converter is this? Doesn't have even the most basic units, like Delisle temp scale. Bah, shame.

Ooh, this should be very useful when reading article written by American journalists.

Kilogram is a unit of mass, not weight. Just an FYI.

Small typo!

Molar Concenration -> Molar Concen(t)ration

Someone tell Randall Munroe

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