Roblox gun damage: range falloff, headshots and armour in Luau

Updated 2026-11-02 · Roblox and game developers · by CyberMax

Copy-paste code

ReplicatedStorage/DamageMath (ModuleScript)

Copylocal DamageMath = {}

-- points: { {range, mult}, ... } sorted by range, e.g. { {50, 1}, {150, 0.6}, {300, 0.4} }
function DamageMath.falloff(points, distance)
	if distance <= points[1][1] then return points[1][2] end
	for i = 2, #points do
		local a, b = points[i - 1], points[i]
		if distance <= b[1] then
			local t = (distance - a[1]) / (b[1] - a[1])
			return a[2] + (b[2] - a[2]) * t
		end
	end
	return points[#points][2]
end

local ZONES = { Head = 1.6, UpperTorso = 1, LowerTorso = 1, Torso = 1, HumanoidRootPart = 1 }
function DamageMath.compute(weapon, distance, partName)
	local zone = ZONES[partName] or 0.85 -- limbs and accessories
	return math.floor(weapon.damage * DamageMath.falloff(weapon.falloff, distance) * zone * 10 + 0.5) / 10
end

-- armour absorbs `soak` of the damage until it runs out
function DamageMath.applyArmour(amount, armour, soak)
	local absorbed = math.min(armour, amount * soak)
	return amount - absorbed, armour - absorbed
end

return DamageMath

Good to know

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