So I found myself needing a fast speed calculation when playing some games (especially in Doubles trying things like TR Victini). I know there are several stat calculators, but I needed something better, something simple and past to calculate speed, so I made a little javascript code to do so. Then I decided to make it better basing it on Honko's damage calc (I hope you don't mind), so I'm using his set js file, which is hosted in Pokemon Showdown, to calculate speed from all Pokemon sets in singles or one versus all, here it is. It's useful mainly for weird situations with different boosts and strange speed tiers, but I already found it useful nonetheless, so I hope you find it useful as well. It works on most navigators, but the set list won't work on Internet Explorer. You can still fill in the fields and calculate in IE since I'm using pure JavaScript for this project.

Your tool says a Timid Venusaur with max speed and an ability that doubles speed is slower than standard Timid Scarf Latios. For some weird reason it ignores the boosting nature (of Venusaur) in this particular case.

Yeah, there was a problem with natures (thanks to adding that short select, hehe) that made it stay on set's nature, but it's now solved: 252 speed EVs 30 IVs Venusaur with Speed Doubling ability and a positive nature is faster than than 252 speed EVs 31 IVs Latios with Choice Scarf and a positive nature. 252 speed EVs 30 IVs Venusaur with Speed Doubling ability and a neutral nature is slower than than 252 speed EVs 31 IVs Latios with Choice Scarf and a positive nature. As you can see I also added a fancy nature text :)

quick feet is supposed to ignore paralysis’ speed reduction, but it doesn’t do so in the calc i mean ofc we could just leave para blank and tick quick feet only but just pointing out a problem also: The Munchlax has a speed of 0. The Deoxys-S has a speed of 18144. 252 speed EVs 31 IVs paralyzed Munchlax with a negative nature is slower than than 252 speed EVs 31 IVs Deoxys-S with Choice Scarf, Tailwind, Quick Feet, Speed Doubling ability and a positive nature. that was a random calc, but why does the calc ignore EVs and IVs? (it doesn’t just put 252 EVs and 31 IVs, it actually uses them for the calc, although i put 0 IVs and 0 EVs)

You have a point, I've changed it so you can check paralyzed and Quick Feet and it just ignores Paralyze on Quick Feet. Also, for some reason EVs and IVs were defaulting to max, but I've solved that now, thanks for noticing :)