How to make percentage drain

lets say the player has 700 stamina at max rank and 300 stamina at starting rank
how can it be the same drain for both

Do you want I write a script to get a percentage of a fraction ?

yes please do that thats what it is thanks

Here is the script! This script will print the percentage of stamina.

local percentage = startingRankStamina / maxRankStamina * 100

You can use the round function

 local percentage = math.round( startingRankStamina / maxRankStamina * 100 )

trying to make it so it drains 0.7% of the stamina every like 0.3 seconds

This is easy. Try this script !

while wait(0.3) do
    startingRankStamina += ( maxRankStamina / 100 )  *  0.7
end

I hope I helped you.

what if the player stamina increases everytime he ranks up

I made an error on my 2nd script?

stamina = 420
local function decreaseStamina(stamina)
  local s = stamina
  if math.abs(stamina*0.99) < 0.001 then
    s = 0;
  end
  return s*0.99
end