I have been trying to figure out what the maximum possible distance that a character can move in a single turn. I have done some calculations and might've figured it out. It has a LVL 18 Wood Elf Monk with 2 LVLs in Fighter for Action Surge, with the Mobile feat and the Longstrider and Haste spells cast on them. They are also wearing the Boots of Speed. The Monk must be standing on the very edge of reach for 35 LVL 17 Warlocks with Eldritch Blast and Repelling Blast, as well as War Caster. The warlocks are of various sizes so that their reach ends in the same spot. The Monk then moves 5 feet going out of their range, triggering an opportunity attack from all the warlocks, launching the Monk 1400 total feet, into a group of 33 other Warlocks, (2 aren't there because they would be within two sizes of the Monk, and would collide with the Monk as he was flying through the air), and the Monk uses another 5 feet of movement to move out of the range of those Warlocks, getting launched another 1320 feet. Repeat the process until you have traveled a whopping 720880 feet in 6 seconds, traveling at Mach 106.766.

Note: It is recommended that the Monk uses a Wish spell to obtain immunity to all force damage, otherwise they would definitely die. Also, this is not meant to be possible in an actual game of DnD, this is just a concept. If you did try to recreate this in an actual DnD game, please note that it will take 17,954 Warlocks to build the full railgun.

2nd Note: I am just going off of the information I have acquired from the Basic Rules for DnD on DnD Beyond and the DnD Player's Handbook, I am not aware of anything else that increases speed and this might not be the true maximum potential of the Warlock Railgun.

bro this is so fast but...

FLYING SPEED?????????

I dont quite understand your question

i mean what if the monk had a flying speed from a spell or magic item of of 35?

 wait wind walk has a flying speed of 300! so you might need a "couple" more warlocks but INSANE SPEED

Flying speeds don't matter because any movement is subtracted from both walking and flying speeds, and with all the current buffs that I talked about, the monk has a movement speed of 2720

but what about in a chase (described in dms manuel) when you can take the dash action as many times as you want?

I was not aware of the chase rules because I don't have access to the DM guide, but after looking up chase in DnD Beyond, it says that a person can dash freely 3 + their Con modifier amount of times.

with good rng and epic boon level CON than its possible to do it over and over

so in a chase you can use dash multiple times but you have to succeed on a 10 CON saving throw or gain one level of exhaustion

so say the monk was being chased by a vampire

so that increases the speed exponentially!

and epic boon level ability scores are 30 and only avalible to 20 level charecters

so they could only fail the save of a nat 1

You could also use a wish spell to stop your aging, and then repeatedly read a manual of bodily health to increase your Con by 2 each time and infinitely dash. But this also just makes the concept of the Warlock Railgun pointless, and that ruins all the fun of getting yeeted at thousands of miles an hour.

YES! Now your getting it!

So the max speed is until you get a 1 out of 64000000

This discussion has basically told me that theoretically, there is no maximum speed, you can just scale infinitely.

at that point sonic becomes a snail

wait oops