diff --git a/lua/autorun/client/speedtest_gui.lua b/lua/autorun/client/speedtest_gui.lua
new file mode 100644
index 0000000..496058d
--- /dev/null
+++ b/lua/autorun/client/speedtest_gui.lua
@@ -0,0 +1,160 @@
+-- clientside speedtest_gui command
+-- Author: utsuho
+-- suggestion by ilker2445
+
+local speedtest_urls = {
+    ["1mb"] = { "http://speedtest.tele2.net/1MB.zip" },
+    ["2mb"] = { "http://speedtest.tele2.net/2MB.zip" },
+    ["5mb"] = { "http://speedtest.tele2.net/5MB.zip" },
+    ["10mb2"] = { "http://ipv4.download.thinkbroadband.com/10MB.zip" },
+    ["100mb"] = { "https://hil-speed.hetzner.com/100MB.bin" },
+    ["100mb2"] = { "http://speedtest.tele2.net/100MB.zip" },
+    ["custom"] = nil,
+}
+
+local function start_speedtest(url, result_label, callback)
+    if not IsValid(result_label) then return end
+
+    result_label:SetText("Starting speed test... Downloading from " .. url)
+
+    local start_time = SysTime()
+    http.Fetch(url,
+        function(_, len)
+            if not IsValid(result_label) then return end
+
+            local end_time = SysTime()
+            local download_time = end_time - start_time
+            if download_time <= 0 then
+                result_label:SetText("Error: Download time is too short to measure speed accurately.")
+                if callback then callback("Error: Download time is too short to measure speed accurately.") end
+                return
+            end
+
+            -- local speed_mbps = (len / time) * (10 ^ -6) * 8
+            -- original calculation from by chat_commands_cl_cmds.lua is no longer used
+            -- new calculation has more accuracy but will error on impossibly fast downloads so we check above
+            local speed_mbps = (len * 8) / (download_time * 1024 * 1024)
+            local result_text = string.format(
+                "speedtest_gui: Download completed in %.2f seconds. File size: %.2f MB. Speed: %.2f Mbps",
+                download_time,
+                len / (1024 * 1024),
+                speed_mbps
+            )
+            result_label:SetText(result_text)
+
+            if callback then callback(result_text) end
+        end,
+        function(error)
+            if not IsValid(result_label) then return end
+
+            local error_text = "Speed test failed: " .. tostring(error)
+            result_label:SetText(error_text)
+            if callback then callback(error_text) end
+        end
+    )
+end
+
+local function open_speedtest_gui()
+    local frame = vgui.Create("DFrame")
+    frame:SetTitle("Speed Test")
+    frame:SetSize(400, 360)
+    frame:Center()
+    frame:MakePopup()
+
+    local dropdown = vgui.Create("DComboBox", frame)
+    dropdown:SetPos(10, 40)
+    dropdown:SetSize(380, 20)
+    dropdown:SetValue("Select File Size")
+    for key, urls in pairs(speedtest_urls) do
+        local display_text = key:upper() .. (urls and (" - " .. urls[1]) or "")
+        dropdown:AddChoice(display_text, key)
+    end
+    dropdown:AddChoice("Custom URL", "custom")
+
+    local url_label = vgui.Create("DLabel", frame)
+    url_label:SetPos(10, 70)
+    url_label:SetSize(380, 20)
+    url_label:SetText("URL: ")
+
+    local custom_url_entry = vgui.Create("DTextEntry", frame)
+    custom_url_entry:SetPos(10, 100)
+    custom_url_entry:SetSize(380, 20)
+    custom_url_entry:SetPlaceholderText("Enter custom URL here")
+    custom_url_entry:SetVisible(false)
+
+    local output_dropdown = vgui.Create("DComboBox", frame)
+    output_dropdown:SetPos(10, 130)
+    output_dropdown:SetSize(380, 20)
+    output_dropdown:SetValue("Show only me")
+    output_dropdown:AddChoice("Show only me")
+    output_dropdown:AddChoice("Say in local")
+    output_dropdown:AddChoice("Say in global")
+
+    local start_button = vgui.Create("DButton", frame)
+    start_button:SetPos(10, 160)
+    start_button:SetSize(380, 30)
+    start_button:SetText("Start Speed Test")
+
+    local result_label = vgui.Create("DLabel", frame)
+    result_label:SetPos(10, 200)
+    result_label:SetSize(380, 60)
+    result_label:SetWrap(true)
+    result_label:SetText("")
+
+    local accuracy_label = vgui.Create("DLabel", frame)
+    accuracy_label:SetPos(10, 270)
+    accuracy_label:SetSize(380, 40)
+    accuracy_label:SetWrap(true)
+    accuracy_label:SetText("Note: Download time may not be super accurate for very small files or fast connections.")
+
+    dropdown.OnSelect = function(_, _, value, data)
+        if data == "custom" then
+            custom_url_entry:SetVisible(true)
+            url_label:SetText("URL: (Enter custom URL below)")
+        else
+            custom_url_entry:SetVisible(false)
+            local url = speedtest_urls[data] and speedtest_urls[data][1]
+            url_label:SetText("URL: " .. (url or ""))
+        end
+    end
+
+    start_button.DoClick = function()
+        local selected = dropdown:GetSelected()
+        local data = dropdown:GetOptionData(dropdown:GetSelectedID())
+        if not selected or not data then
+            result_label:SetText("Please select a file size.")
+            return
+        end
+
+        local url
+        if data == "custom" then
+            url = custom_url_entry:GetValue()
+            if url == "" then
+                result_label:SetText("Please enter a valid custom URL.")
+                return
+            end
+        else
+            local urls = speedtest_urls[data]
+            url = urls and urls[1]
+        end
+
+        if url then
+            start_speedtest(url, result_label, function(result_text)
+                local output_type = output_dropdown:GetSelected()
+                if output_type == "Show only me" then
+                    chat.AddText(result_text)
+                elseif output_type == "Say in local" then
+                    SayLocal(result_text)
+                elseif output_type == "Say in global" then
+                    Say(result_text)
+                else
+                    chat.AddText("Invalid output type selected.")
+                end
+            end)
+        else
+            result_label:SetText("Invalid selection.")
+        end
+    end
+end
+
+concommand.Add("speedtest_gui", open_speedtest_gui)