diff --git a/web/src/lib/term-format.test.ts b/web/src/lib/term-format.test.ts
new file mode 100644
index 0000000..0a64f8e
--- /dev/null
+++ b/web/src/lib/term-format.test.ts
@@ -0,0 +1,64 @@
+import { describe, it, expect } from "vitest";
+import { termToFriendly, termToBanner } from "./term-format";
+
+describe("termToFriendly", () => {
+  it("converts spring term correctly", () => {
+    expect(termToFriendly("202610")).toBe("spring-26");
+    expect(termToFriendly("202510")).toBe("spring-25");
+  });
+
+  it("converts summer term correctly", () => {
+    expect(termToFriendly("202620")).toBe("summer-26");
+    expect(termToFriendly("202520")).toBe("summer-25");
+  });
+
+  it("converts fall term correctly", () => {
+    expect(termToFriendly("202630")).toBe("fall-26");
+    expect(termToFriendly("202530")).toBe("fall-25");
+  });
+
+  it("returns null for invalid codes", () => {
+    expect(termToFriendly("20261")).toBe(null);
+    expect(termToFriendly("2026100")).toBe(null);
+    expect(termToFriendly("202640")).toBe(null); // Invalid semester code
+    expect(termToFriendly("")).toBe(null);
+  });
+});
+
+describe("termToBanner", () => {
+  it("converts spring term correctly", () => {
+    expect(termToBanner("spring-26")).toBe("202610");
+    expect(termToBanner("spring-25")).toBe("202510");
+  });
+
+  it("converts summer term correctly", () => {
+    expect(termToBanner("summer-26")).toBe("202620");
+    expect(termToBanner("summer-25")).toBe("202520");
+  });
+
+  it("converts fall term correctly", () => {
+    expect(termToBanner("fall-26")).toBe("202630");
+    expect(termToBanner("fall-25")).toBe("202530");
+  });
+
+  it("returns null for invalid formats", () => {
+    expect(termToBanner("winter-26")).toBe(null);
+    expect(termToBanner("spring26")).toBe(null);
+    expect(termToBanner("spring-2026")).toBe(null);
+    expect(termToBanner("26-spring")).toBe(null);
+    expect(termToBanner("")).toBe(null);
+  });
+});
+
+describe("round-trip conversion", () => {
+  it("converts back and forth correctly", () => {
+    const bannerCodes = ["202610", "202620", "202630", "202510"];
+
+    for (const code of bannerCodes) {
+      const friendly = termToFriendly(code);
+      expect(friendly).not.toBeNull();
+      const backToBanner = termToBanner(friendly!);
+      expect(backToBanner).toBe(code);
+    }
+  });
+});
diff --git a/web/src/lib/term-format.ts b/web/src/lib/term-format.ts
new file mode 100644
index 0000000..ae31e7d
--- /dev/null
+++ b/web/src/lib/term-format.ts
@@ -0,0 +1,48 @@
+/**
+ * Convert between Banner's internal term codes (e.g., "202620") and human-friendly format (e.g., "summer-26")
+ */
+
+export type SemesterName = "spring" | "summer" | "fall";
+
+const SEMESTER_CODES: Record<string, SemesterName> = {
+  "10": "spring",
+  "20": "summer",
+  "30": "fall",
+};
+
+const SEMESTER_TO_CODE: Record<SemesterName, string> = {
+  spring: "10",
+  summer: "20",
+  fall: "30",
+};
+
+/**
+ * Convert Banner term code (e.g., "202620") to friendly format (e.g., "summer-26")
+ */
+export function termToFriendly(bannerCode: string): string | null {
+  if (bannerCode.length !== 6) return null;
+
+  const year = bannerCode.substring(0, 4);
+  const semesterCode = bannerCode.substring(4, 6);
+  const semester = SEMESTER_CODES[semesterCode];
+
+  if (!semester) return null;
+
+  const shortYear = year.substring(2, 4);
+  return `${semester}-${shortYear}`;
+}
+
+/**
+ * Convert friendly format (e.g., "summer-26") to Banner term code (e.g., "202620")
+ */
+export function termToBanner(friendly: string): string | null {
+  const match = friendly.match(/^(spring|summer|fall)-(\d{2})$/);
+  if (!match) return null;
+
+  const [, semester, shortYear] = match;
+  const semesterCode = SEMESTER_TO_CODE[semester as SemesterName];
+  if (!semesterCode) return null;
+
+  const fullYear = `20${shortYear}`;
+  return `${fullYear}${semesterCode}`;
+}
diff --git a/web/src/routes/+page.svelte b/web/src/routes/+page.svelte
index 82e5669..c41ea6a 100644
--- a/web/src/routes/+page.svelte
+++ b/web/src/routes/+page.svelte
@@ -14,14 +14,17 @@ import SearchStatus, { type SearchMeta } from "$lib/components/SearchStatus.svel
 import CourseTable from "$lib/components/CourseTable.svelte";
 import Pagination from "$lib/components/Pagination.svelte";
 import Footer from "$lib/components/Footer.svelte";
+import { termToBanner, termToFriendly } from "$lib/term-format";
 
 let { data } = $props();
 
 // Read initial state from URL params (intentionally captured once)
 const initialParams = untrack(() => new URLSearchParams(data.url.search));
 
-// Filter state
-let selectedTerm = $state(untrack(() => initialParams.get("term") ?? data.terms[0]?.code ?? ""));
+// Filter state - only set term from URL if present (no auto-default)
+const urlTerm = initialParams.get("term");
+const bannerTerm = urlTerm ? (termToBanner(urlTerm) ?? "") : "";
+let selectedTerm = $state(bannerTerm);
 let selectedSubjects: string[] = $state(untrack(() => initialParams.getAll("subject")));
 let query = $state(initialParams.get("q") ?? "");
 let openOnly = $state(initialParams.get("open") === "true");
@@ -160,7 +163,10 @@ async function performSearch(
     sort.length > 0 ? (sort[0].desc ? "desc" : "asc") : undefined;
 
   const params = new URLSearchParams();
-  params.set("term", term);
+  const friendlyTerm = termToFriendly(term);
+  if (friendlyTerm) {
+    params.set("term", friendlyTerm);
+  }
   for (const s of subjects) {
     params.append("subject", s);
   }