diff --git a/ui/index.html b/ui/index.html
index cf3ee74b9..c596c2849 100644
--- a/ui/index.html
+++ b/ui/index.html
@@ -10,7 +10,6 @@
 
     <script>
         const global = globalThis;
-        const base = "{{ . }}";
     </script>
     <base href="{{ . }}ui/" />
   </head>
diff --git a/ui/src/util/basePaths.spec.ts b/ui/src/util/basePaths.spec.ts
index b7d908db0..cc661e780 100644
--- a/ui/src/util/basePaths.spec.ts
+++ b/ui/src/util/basePaths.spec.ts
@@ -5,34 +5,59 @@ import {
 } from "./basePaths";
 
 vi.mock("./basePaths", async () => {
-  window.base = "/example";
+  const basePath = "/example/ui";
+  // Can't use the setBase function here as this mock gets hoisted to the top of
+  // the file so gets executed before setBase exists.
+  const base = document.createElement("base");
+  base.setAttribute("href", basePath);
+  document.body.appendChild(base);
   const actual = await vi.importActual("./basePaths");
   return {
     ...actual,
-    basePath: "/example/ui/",
-    apiBasePath: "/example/api/v0/",
+    basePath,
   };
 });
 
+const cleanBase = () =>
+  document.querySelectorAll("base").forEach((base) => {
+    document.body.removeChild(base);
+  });
+
+const setBase = (href: string) => {
+  const base = document.createElement("base");
+  base.setAttribute("href", href);
+  document.body.appendChild(base);
+};
+
+// Clean up the base created by the mock above.
+cleanBase();
+
 describe("calculateBasePath", () => {
+  afterEach(() => {
+    cleanBase();
+  });
+
   it("resolves with ui path", () => {
-    window.base = "/test/";
+    setBase("/test/");
     const result = calculateBasePath();
     expect(result).toBe("/test/");
   });
 
   it("resolves with ui path without trailing slash", () => {
-    window.base = "/test";
+    setBase("/test");
+    const result = calculateBasePath();
+    expect(result).toBe("/test/");
+  });
+
+  it("handles full URL", () => {
+    setBase("http://example.com/test/");
     const result = calculateBasePath();
     expect(result).toBe("/test/");
   });
 
-  it("resolves with root path if the base is not provided", () => {
-    if (window.base) {
-      delete window.base;
-    }
+  it("resolves if the base is not provided", () => {
     const result = calculateBasePath();
-    expect(result).toBe("/");
+    expect(result).toBe("/ui/");
   });
 });
 
@@ -48,10 +73,10 @@ describe("appendBasePath", () => {
 
 describe("appendAPIBasePath", () => {
   it("handles paths with a leading slash", () => {
-    expect(appendAPIBasePath("/test")).toBe("/example/api/v0/test");
+    expect(appendAPIBasePath("/test")).toBe("/api/v0/test");
   });
 
   it("handles paths without a leading slash", () => {
-    expect(appendAPIBasePath("test")).toBe("/example/api/v0/test");
+    expect(appendAPIBasePath("test")).toBe("/api/v0/test");
   });
 });
diff --git a/ui/src/util/basePaths.ts b/ui/src/util/basePaths.ts
index 1f9d9d8d0..d8c428fe8 100644
--- a/ui/src/util/basePaths.ts
+++ b/ui/src/util/basePaths.ts
@@ -1,25 +1,18 @@
 import { removeTrailingSlash } from "util/removeTrailingSlash";
+import { getFullPath } from "./getFullPath";
 type BasePath = `/${string}`;
 
-declare global {
-  interface Window {
-    base?: string;
-  }
-}
-
 export const calculateBasePath = (): BasePath => {
-  let basePath = "";
-  if ("base" in window && typeof window.base === "string") {
-    basePath = window.base;
-  }
-  if (basePath) {
-    return `${removeTrailingSlash(basePath)}/` as BasePath;
+  const basePath = document.querySelector("base")?.href;
+  const path = basePath ? getFullPath(basePath) : null;
+  if (path) {
+    return `${removeTrailingSlash(path)}/` as BasePath;
   }
-  return "/";
+  return "/ui/";
 };
 
-export const basePath: BasePath = `${calculateBasePath()}ui`;
-export const apiBasePath: BasePath = `${calculateBasePath()}api/v0/`;
+export const basePath: BasePath = calculateBasePath();
+export const apiBasePath: BasePath = "/api/v0/";
 
 export const appendBasePath = (path: string) =>
   `${removeTrailingSlash(basePath)}/${path.replace(/^\//, "")}`;