Scripting | FPS Log

There is a lot of posts about your topic. Using this Post about FPS, It appears that there there is 3 ways to do this:

You could get the PhysicsFPS:

workspace:GetRealPhysicsFPS()

That this is probably not what your looking for, but someone else linked a script to get the Clients FPS:

local RunService = game:GetService("RunService")
local FpsLabel = script.Parent

local TimeFunction = RunService:IsRunning() and time or os.clock

local LastIteration, Start
local FrameUpdateTable = {}

local function HeartbeatUpdate()
	LastIteration = TimeFunction()
	for Index = #FrameUpdateTable, 1, -1 do
		FrameUpdateTable[Index + 1] = FrameUpdateTable[Index] >= LastIteration - 1 and FrameUpdateTable[Index] or nil
	end

	FrameUpdateTable[1] = LastIteration
	FpsLabel.Text = tostring(math.floor(TimeFunction() - Start >= 1 and #FrameUpdateTable or #FrameUpdateTable / (TimeFunction() - Start))) .. " FPS"
end

Start = TimeFunction()
RunService.Heartbeat:Connect(HeartbeatUpdate)

or

function getFps()

return (1/game:GetService("RunService").RenderStepped:Wait())

end
local FPS = getFps()