Help with healthbar math

[Chaotic_Skulls (Chaotic)]

I need to make a healthbar that goes from a normal bar into a circular bar after 50% of the health is lost

the bar im using is shown in this image
(the bar and circle are in the same imagelabel)
im trying to do this using a gradient with offset and rotation

[STOOK_X]

I would suggest using some simple math or tween for the bar. Then have the script check if the players health is under 50% then for the circle you can do what Roblox dose for there proximity prompts. What they basically do is have a gradient and then they use math to change the orientation and size of it so it looks like a circular moving bar. (So yeah what you are already doing is good )

So something like this maby…

local gradient = imageLabel:FindFirstChildOfClass("UIGradient")

-- assume health is from 0 to 100
function updateHealthbar(health)
	local percent = math.clamp(health / 100, 0, 1)

	if percent > 0.5 then
		-- Reveal left-to-right bar
		local t = (percent - 0.5) * 2 -- Remap 0.5–1 to 0–1
		gradient.Rotation = 0
		gradient.Offset = Vector2.new(-1 + t, 0) -- Shift from -1 to 0
	else
		-- Reveal circular part
		local t = percent * 2 -- Remap 0–0.5 to 0–1
		gradient.Rotation = 90 -- or 180 depending on circle layout
		gradient.Offset = Vector2.new(-1 + t, 0) -- Shift again
	end
end

[STOOK_X]

You can also tween it for a smoother look

game:GetService("TweenService"):Create(gradient, TweenInfo.new(0.2), {
    Offset = Vector2.new(...),
    Rotation = ...
}):Play()

[Chaotic_Skulls (Chaotic)]

While this response is nice this isnt exactly what im looking for i already know how i would need to do it
This is the code i currently have the math might be a bit messy, (gradient starts at 1,1 and not at 0,0)
im also calculating it by 1.1 cause it otherwise looks weird
( also sorry i decided to make it start at 40% now and not 50%)

local HPbar = game.Workspace["3DHPBARATTEMPT"]
local Gradient = script.Parent.UIGradient

local CircularStart = 0.4

HPbar:GetAttributeChangedSignal("HP"):Connect(function()
	local HP = HPbar:GetAttribute("HP")
	if HP > 40 then 
		HP = 80 + (HP-90) 
	end
	local Calc = math.clamp(HP/100,0,1) * 1.1
	if Calc > CircularStart then
		Gradient.Rotation = 0
		Gradient.Offset = Vector2.new(Calc,1)
	else
		--empty cause idk what to calculate
	end
end)

the thing i would need to rotate the gradient and change the offset at the same time while the health changes, atleast thats what im guessing i have to do
i have been at this for a few hours already and just cant figure out the math
cause the health ends here

40% mark starts around here on the gradient

[Chaotic_Skulls (Chaotic)]

im gonna try to post a rbxm file of the hp bar later just need to talk with the designer of this if hes fine with it being shared here