diff --git a/src/app/components/shared/SizeBadge.tsx b/src/app/components/shared/SizeBadge.tsx
index b3ddf999..afb3b656 100644
--- a/src/app/components/shared/SizeBadge.tsx
+++ b/src/app/components/shared/SizeBadge.tsx
@@ -6,7 +6,7 @@ interface SizeBadgeProps {
   additions: number;
   deletions: number;
   changedFiles: number;
-  category?: "XS" | "S" | "M" | "L" | "XL";
+  category?: "XS" | "S" | "M" | "L" | "XL" | "XXL";
   filesUrl?: string;
 }
 
@@ -16,14 +16,16 @@ const SIZE_CONFIG = {
   M: "badge badge-warning badge-sm",
   L: "badge badge-error badge-sm",
   XL: "badge badge-error badge-sm",
+  XXL: "badge badge-error badge-sm",
 } as const;
 
-const SIZE_TOOLTIP: Record<"XS" | "S" | "M" | "L" | "XL", string> = {
+const SIZE_TOOLTIP: Record<"XS" | "S" | "M" | "L" | "XL" | "XXL", string> = {
   XS: "XS: <10 lines changed",
-  S: "S: 10–99 lines changed",
-  M: "M: 100–499 lines changed",
-  L: "L: 500–999 lines changed",
-  XL: "XL: 1000+ lines changed",
+  S: "S: 10–29 lines changed",
+  M: "M: 30–99 lines changed",
+  L: "L: 100–499 lines changed",
+  XL: "XL: 500–999 lines changed",
+  XXL: "XXL: 1000+ lines changed",
 };
 
 export default function SizeBadge(props: SizeBadgeProps) {
diff --git a/src/app/components/shared/filterTypes.ts b/src/app/components/shared/filterTypes.ts
index b733431b..40fd7ccf 100644
--- a/src/app/components/shared/filterTypes.ts
+++ b/src/app/components/shared/filterTypes.ts
@@ -84,6 +84,7 @@ export const prFilterGroups: FilterChipGroupDef[] = [
       { value: "M", label: "M" },
       { value: "L", label: "L" },
       { value: "XL", label: "XL" },
+      { value: "XXL", label: "XXL" },
     ],
   },
 ];
diff --git a/src/app/stores/view.ts b/src/app/stores/view.ts
index 36582dce..af298b26 100644
--- a/src/app/stores/view.ts
+++ b/src/app/stores/view.ts
@@ -32,7 +32,7 @@ export const PullRequestFiltersSchema = z.object({
   reviewDecision: z.enum(["all", "APPROVED", "CHANGES_REQUESTED", "REVIEW_REQUIRED", "mergeable"]).default("all"),
   draft: z.enum(["all", "draft", "ready"]).default("all"),
   checkStatus: z.enum(["all", "success", "failure", "pending", "conflict", "blocked", "none"]).default("all"),
-  sizeCategory: z.enum(["all", "XS", "S", "M", "L", "XL"]).default("all"),
+  sizeCategory: z.enum(["all", "XS", "S", "M", "L", "XL", "XXL"]).default("all"),
   user: z.enum(["all"]).or(z.string()).default("all"),
 });
 
diff --git a/src/shared/format.ts b/src/shared/format.ts
index 4a73871e..1dd8a7f4 100644
--- a/src/shared/format.ts
+++ b/src/shared/format.ts
@@ -83,13 +83,14 @@ export function formatDuration(startedAt: string, completedAt: string | null): s
 /**
  * Categorizes a PR by size based on total lines changed.
  */
-export function prSizeCategory(additions: number, deletions: number): "XS" | "S" | "M" | "L" | "XL" {
+export function prSizeCategory(additions: number, deletions: number): "XS" | "S" | "M" | "L" | "XL" | "XXL" {
   const total = (additions || 0) + (deletions || 0);
   if (total < 10) return "XS";
-  if (total < 100) return "S";
-  if (total < 500) return "M";
-  if (total < 1000) return "L";
-  return "XL";
+  if (total < 30) return "S";
+  if (total < 100) return "M";
+  if (total < 500) return "L";
+  if (total < 1000) return "XL";
+  return "XXL";
 }
 
 /**
diff --git a/tests/components/PullRequestsTab.test.tsx b/tests/components/PullRequestsTab.test.tsx
index dc1dc28d..b92c2415 100644
--- a/tests/components/PullRequestsTab.test.tsx
+++ b/tests/components/PullRequestsTab.test.tsx
@@ -166,10 +166,9 @@ describe("PullRequestsTab", () => {
     const pr = makePullRequest({ id: 1, title: "Big PR", additions: 300, deletions: 100, repoFullName: "org/repo-a" });
     setAllExpanded("pullRequests", ["org/repo-a"], true);
     render(() => <PullRequestsTab pullRequests={[pr]} userLogin="" />);
-    // prSizeCategory(300, 100) = 400 total -> M
-    // "M" appears as a size badge
-    const mEls = screen.getAllByText("M");
-    const badgeEl = mEls.find((el) => el.tagName.toLowerCase() === "span");
+    // prSizeCategory(300, 100) = 400 total -> L
+    const lEls = screen.getAllByText("L");
+    const badgeEl = lEls.find((el) => el.tagName.toLowerCase() === "span");
     expect(badgeEl).toBeDefined();
   });
 
@@ -245,6 +244,18 @@ describe("PullRequestsTab", () => {
     expect(screen.queryByText("Large PR")).toBeNull();
   });
 
+  it("filters by sizeCategory 'XXL' tab filter", () => {
+    const prs = [
+      makePullRequest({ id: 1, title: "Huge PR", additions: 800, deletions: 500, repoFullName: "org/repo-a" }),
+      makePullRequest({ id: 2, title: "Medium PR", additions: 30, deletions: 20, repoFullName: "org/repo-a" }),
+    ];
+    viewStore.setTabFilter("pullRequests", "sizeCategory", "XXL");
+    setAllExpanded("pullRequests", ["org/repo-a"], true);
+    render(() => <PullRequestsTab pullRequests={prs} userLogin="" />);
+    screen.getByText("Huge PR");
+    expect(screen.queryByText("Medium PR")).toBeNull();
+  });
+
   it("groups PRs by repo with collapsible headers", () => {
     const prs = [
       makePullRequest({ id: 1, title: "PR in repo A", repoFullName: "org/repo-a" }),
diff --git a/tests/components/shared-badges.test.tsx b/tests/components/shared-badges.test.tsx
index 82a78018..fcc0a286 100644
--- a/tests/components/shared-badges.test.tsx
+++ b/tests/components/shared-badges.test.tsx
@@ -1,4 +1,4 @@
-import { describe, it, expect, vi } from "vitest";
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
 import { render, screen, fireEvent } from "@solidjs/testing-library";
 import RoleBadge from "../../src/app/components/shared/RoleBadge";
 import ReviewBadge from "../../src/app/components/shared/ReviewBadge";
@@ -67,9 +67,29 @@ describe("SizeBadge", () => {
     screen.getByText("1 file");
   });
 
-  it("renders XL badge for large changes", () => {
-    render(() => <SizeBadge additions={800} deletions={500} changedFiles={42} />);
+  it("renders S badge for small-medium changes", () => {
+    render(() => <SizeBadge additions={15} deletions={14} changedFiles={2} />);
+    screen.getByText("S");
+  });
+
+  it("renders M badge for medium changes", () => {
+    render(() => <SizeBadge additions={15} deletions={15} changedFiles={3} />);
+    screen.getByText("M");
+  });
+
+  it("renders L badge for large changes", () => {
+    render(() => <SizeBadge additions={200} deletions={100} changedFiles={10} />);
+    screen.getByText("L");
+  });
+
+  it("renders XL badge for extra-large changes", () => {
+    render(() => <SizeBadge additions={400} deletions={200} changedFiles={20} />);
     screen.getByText("XL");
+  });
+
+  it("renders XXL badge for large changes", () => {
+    render(() => <SizeBadge additions={800} deletions={500} changedFiles={42} />);
+    screen.getByText("XXL");
     screen.getByText("+800");
     screen.getByText("-500");
     screen.getByText("42 files");
@@ -85,18 +105,47 @@ describe("SizeBadge", () => {
     screen.getByText("XS");
   });
 
-  it("shows tooltip with size description on hover", () => {
-    vi.useFakeTimers();
-    const { container } = render(() => (
-      <SizeBadge additions={3} deletions={2} changedFiles={1} />
-    ));
-    const trigger = container.querySelector("span.inline-flex");
-    expect(trigger).not.toBeNull();
-    fireEvent.pointerEnter(trigger!);
-    vi.advanceTimersByTime(300);
-    expect(document.body.textContent).toContain("XS: <10 lines changed");
-    fireEvent.pointerLeave(trigger!);
-    vi.advanceTimersByTime(500);
-    vi.useRealTimers();
+  describe("tooltips", () => {
+    beforeEach(() => vi.useFakeTimers());
+    afterEach(() => vi.useRealTimers());
+
+    it("shows tooltip with size description on hover", () => {
+      const { container } = render(() => (
+        <SizeBadge additions={3} deletions={2} changedFiles={1} />
+      ));
+      const trigger = container.querySelector("span.inline-flex");
+      expect(trigger).not.toBeNull();
+      fireEvent.pointerEnter(trigger!);
+      vi.advanceTimersByTime(300);
+      expect(document.body.textContent).toContain("XS: <10 lines changed");
+      fireEvent.pointerLeave(trigger!);
+      vi.advanceTimersByTime(500);
+    });
+
+    it("shows tooltip with S size description on hover", () => {
+      const { container } = render(() => (
+        <SizeBadge additions={10} deletions={5} changedFiles={2} />
+      ));
+      const trigger = container.querySelector("span.inline-flex");
+      expect(trigger).not.toBeNull();
+      fireEvent.pointerEnter(trigger!);
+      vi.advanceTimersByTime(300);
+      expect(document.body.textContent).toContain("S: 10–29 lines changed");
+      fireEvent.pointerLeave(trigger!);
+      vi.advanceTimersByTime(500);
+    });
+
+    it("shows tooltip with XXL size description on hover", () => {
+      const { container } = render(() => (
+        <SizeBadge additions={800} deletions={500} changedFiles={42} />
+      ));
+      const trigger = container.querySelector("span.inline-flex");
+      expect(trigger).not.toBeNull();
+      fireEvent.pointerEnter(trigger!);
+      vi.advanceTimersByTime(300);
+      expect(document.body.textContent).toContain("XXL: 1000+ lines changed");
+      fireEvent.pointerLeave(trigger!);
+      vi.advanceTimersByTime(500);
+    });
   });
 });
diff --git a/tests/lib/format.test.ts b/tests/lib/format.test.ts
index 9234cfaa..07ea7893 100644
--- a/tests/lib/format.test.ts
+++ b/tests/lib/format.test.ts
@@ -238,20 +238,24 @@ describe("prSizeCategory", () => {
     expect(prSizeCategory(3, 2)).toBe("XS");
   });
 
-  it("returns S for total 10-99", () => {
-    expect(prSizeCategory(50, 30)).toBe("S");
+  it("returns S for total 10-29", () => {
+    expect(prSizeCategory(10, 5)).toBe("S");
   });
 
-  it("returns M for total 100-499", () => {
-    expect(prSizeCategory(200, 100)).toBe("M");
+  it("returns M for total 30-99", () => {
+    expect(prSizeCategory(50, 30)).toBe("M");
   });
 
-  it("returns L for total 500-999", () => {
-    expect(prSizeCategory(600, 200)).toBe("L");
+  it("returns L for total 100-499", () => {
+    expect(prSizeCategory(200, 100)).toBe("L");
   });
 
-  it("returns XL for total >= 1000", () => {
-    expect(prSizeCategory(800, 500)).toBe("XL");
+  it("returns XL for total 500-999", () => {
+    expect(prSizeCategory(600, 200)).toBe("XL");
+  });
+
+  it("returns XXL for total >= 1000", () => {
+    expect(prSizeCategory(800, 500)).toBe("XXL");
   });
 
   it("returns XS for (0, 0)", () => {
@@ -266,12 +270,36 @@ describe("prSizeCategory", () => {
     expect(prSizeCategory(5, 5)).toBe("S");
   });
 
-  it("returns L for total 999 (boundary below 1000)", () => {
-    expect(prSizeCategory(500, 499)).toBe("L");
+  it("returns S for total 29 (boundary below 30)", () => {
+    expect(prSizeCategory(15, 14)).toBe("S");
+  });
+
+  it("returns M for total 30 (boundary at 30)", () => {
+    expect(prSizeCategory(15, 15)).toBe("M");
+  });
+
+  it("returns M for total 99 (boundary below 100)", () => {
+    expect(prSizeCategory(50, 49)).toBe("M");
+  });
+
+  it("returns L for total 100 (boundary at 100)", () => {
+    expect(prSizeCategory(50, 50)).toBe("L");
+  });
+
+  it("returns L for total 499 (boundary below 500)", () => {
+    expect(prSizeCategory(250, 249)).toBe("L");
+  });
+
+  it("returns XL for total 500 (boundary at 500)", () => {
+    expect(prSizeCategory(250, 250)).toBe("XL");
+  });
+
+  it("returns XL for total 999 (boundary below 1000)", () => {
+    expect(prSizeCategory(500, 499)).toBe("XL");
   });
 
-  it("returns XL for total 1000 (boundary at 1000)", () => {
-    expect(prSizeCategory(500, 500)).toBe("XL");
+  it("returns XXL for total 1000 (boundary at 1000)", () => {
+    expect(prSizeCategory(500, 500)).toBe("XXL");
   });
 
   it("handles NaN/undefined gracefully — defaults to XS", () => {