Think it needs some more instructions. "26.2 in 4" gives nothing. Clicking on "marathon" gives nothing. Only when you've typed in a valid (with no real hints) distance does it tell you what's a valid duration.

Also it seems very confused: "100y in 16m" says "Zoom! That's almost as fast as a James Bond car heli-skiing in the Swiss Alps." I'm pretty sure he was going faster than 9km a day there...

Thanks! Yeah I've played around with instructions a few times but it could definitely be clearer.

I'm a former college distance runner. This is neat. I always converted pace in my head, but this would be useful as an app I could quickly check. Since it's presumably all frontend JS, have you considered enabling it as an offline app so people can keep it on their home screen? I've done this before and it's pretty easy - you just need to make sure to include a cache manifest listing all the files required to run offline, and a favicon set with icons for iOS/android (google "favicon generator").

In terms of mobile UI, it might be nice to eliminate the need to scroll to see results. See if you can fit the whole interaction in one screen (maybe push up the inputs to make room for the results).

Thanks for the feedback! I'll see what I can do to make the results easier to see on mobile. I have thought about looking into making it offline; haven't gotten around to that yet but I'll prioritize it higher!

Rounding to the nearest second would be fine. Including the pace for 400 meters would be nice for track-oriented users.

Thanks! That's super helpful.

Hey HN! I'm a runner and was unhappy with all of the pace calculator websites I could find—they were awkward, slow, confusing, couldn't handle arbitrary distances, or couldn't extrapolate, say, a mile pace into a 10k time. This is my attempt at something less terrible!

I'd really appreciate any feedback!