diff --git a/frontend/src/lib/document/timeline.spec.ts b/frontend/src/lib/document/timeline.spec.ts
index 63d9b58b..097705f5 100644
--- a/frontend/src/lib/document/timeline.spec.ts
+++ b/frontend/src/lib/document/timeline.spec.ts
@@ -5,6 +5,7 @@ import {
 	buildMonthSequence,
 	fillDensityGaps,
 	fetchDensity,
+	buildDensityUrl,
 	aggregateToYears,
 	selectionBoundaryFrom,
 	selectionBoundaryTo
@@ -152,6 +153,39 @@ describe('selectionBoundaryFrom / To', () => {
 	});
 });
 
+describe('buildDensityUrl', () => {
+	it('returns the bare endpoint when no filters provided', () => {
+		expect(buildDensityUrl()).toBe('/api/documents/density');
+	});
+
+	it('forwards single-value filters as query params', () => {
+		expect(buildDensityUrl({ q: 'Brief', senderId: 's-1' })).toBe(
+			'/api/documents/density?q=Brief&senderId=s-1'
+		);
+	});
+
+	it('repeats the tag param for multi-value tag filters', () => {
+		const url = buildDensityUrl({ tags: ['Familie', 'Urlaub'], tagOp: 'OR' });
+		expect(url).toContain('tag=Familie');
+		expect(url).toContain('tag=Urlaub');
+		expect(url).toContain('tagOp=OR');
+	});
+
+	it('omits tagOp when it is AND (default on backend)', () => {
+		const url = buildDensityUrl({ tags: ['Familie'], tagOp: 'AND' });
+		expect(url).not.toContain('tagOp=');
+	});
+
+	it('does not forward from/to even if a caller mistakenly adds them', () => {
+		// Intentional: density is the surface for picking from/to, so it must always
+		// span the broader space the user is selecting within.
+		// @ts-expect-error - from/to are explicitly absent from DensityFilters
+		const url = buildDensityUrl({ q: 'Brief', from: '1915-01-01', to: '1916-12-31' });
+		expect(url).not.toContain('from=');
+		expect(url).not.toContain('to=');
+	});
+});
+
 describe('fetchDensity', () => {
 	it('skips fetch and returns null density on mobile', async () => {
 		const fetch = vi.fn();
@@ -189,6 +223,19 @@ describe('fetchDensity', () => {
 		expect(result.maxDate).toBe('1916-12-31');
 	});
 
+	it('forwards active filters as query params', async () => {
+		const fetch = vi.fn().mockResolvedValue({
+			ok: true,
+			json: async () => ({ buckets: [], minDate: null, maxDate: null })
+		});
+
+		await fetchDensity(fetch, null, true, { senderId: 's-1', tags: ['Familie'] });
+
+		const calledWith = fetch.mock.calls[0][0] as string;
+		expect(calledWith).toContain('senderId=s-1');
+		expect(calledWith).toContain('tag=Familie');
+	});
+
 	it('returns empty density and null bounds when the API responds non-ok', async () => {
 		const fetch = vi.fn().mockResolvedValue({ ok: false, status: 500 });
 
diff --git a/frontend/src/lib/document/timeline.ts b/frontend/src/lib/document/timeline.ts
index c82786ad..ac6836bb 100644
--- a/frontend/src/lib/document/timeline.ts
+++ b/frontend/src/lib/document/timeline.ts
@@ -85,6 +85,38 @@ export function selectionBoundaryTo(label: string): string {
 	return monthBoundaryTo(label);
 }
 
+/**
+ * The subset of /documents URL params that should narrow the density chart.
+ * Date bounds (`from`/`to`) are intentionally excluded — see
+ * {@link fetchDensity} for why.
+ */
+export type DensityFilters = {
+	q?: string;
+	senderId?: string;
+	receiverId?: string;
+	tags?: string[];
+	tagQ?: string;
+	status?: string;
+	tagOp?: 'AND' | 'OR';
+};
+
+/**
+ * Builds the density endpoint URL, including the active non-date filters
+ * so the chart matches the document list it sits above.
+ */
+export function buildDensityUrl(filters: DensityFilters = {}): string {
+	const params = new URLSearchParams();
+	if (filters.q) params.set('q', filters.q);
+	if (filters.senderId) params.set('senderId', filters.senderId);
+	if (filters.receiverId) params.set('receiverId', filters.receiverId);
+	for (const tag of filters.tags ?? []) params.append('tag', tag);
+	if (filters.tagQ) params.set('tagQ', filters.tagQ);
+	if (filters.status) params.set('status', filters.status);
+	if (filters.tagOp === 'OR') params.set('tagOp', 'OR');
+	const qs = params.toString();
+	return qs ? `/api/documents/density?${qs}` : '/api/documents/density';
+}
+
 /**
  * Loads the density data for the timeline widget. Mobile (sm: breakpoint and below)
  * and calendar view both skip the request entirely — the widget isn't rendered
@@ -94,12 +126,13 @@ export function selectionBoundaryTo(label: string): string {
 export async function fetchDensity(
 	fetch: typeof globalThis.fetch,
 	view: string | null,
-	isDesktop: boolean
+	isDesktop: boolean,
+	filters: DensityFilters = {}
 ): Promise<DensityState> {
 	if (!isDesktop || view === 'calendar') return SKIP;
 
 	try {
-		const response = await fetch('/api/documents/density');
+		const response = await fetch(buildDensityUrl(filters));
 		if (!response.ok) return EMPTY;
 		const body = (await response.json()) as DocumentDensityResult;
 		return {
diff --git a/frontend/src/lib/generated/api.ts b/frontend/src/lib/generated/api.ts
index 81ae2d19..592a3a9c 100644
--- a/frontend/src/lib/generated/api.ts
+++ b/frontend/src/lib/generated/api.ts
@@ -2253,14 +2253,14 @@ export interface components {
             /** Format: int32 */
             totalPages?: number;
             pageable?: components["schemas"]["PageableObject"];
+            first?: boolean;
+            last?: boolean;
             /** Format: int32 */
             size?: number;
             content?: components["schemas"]["NotificationDTO"][];
             /** Format: int32 */
             number?: number;
             sort?: components["schemas"]["SortObject"];
-            first?: boolean;
-            last?: boolean;
             /** Format: int32 */
             numberOfElements?: number;
             empty?: boolean;
@@ -4959,8 +4959,15 @@ export interface operations {
     density: {
         parameters: {
             query?: {
-                from?: string;
-                to?: string;
+                q?: string;
+                senderId?: string;
+                receiverId?: string;
+                tag?: string[];
+                tagQ?: string;
+                /** @description Filter by document status */
+                status?: "PLACEHOLDER" | "UPLOADED" | "TRANSCRIBED" | "REVIEWED" | "ARCHIVED";
+                /** @description Tag operator: AND (default) or OR */
+                tagOp?: string;
             };
             header?: never;
             path?: never;
diff --git a/frontend/src/routes/documents/+page.ts b/frontend/src/routes/documents/+page.ts
index 0127696a..d79459bb 100644
--- a/frontend/src/routes/documents/+page.ts
+++ b/frontend/src/routes/documents/+page.ts
@@ -1,10 +1,23 @@
 import { browser } from '$app/environment';
-import { fetchDensity } from '$lib/document/timeline';
+import { fetchDensity, type DensityFilters } from '$lib/document/timeline';
 import type { PageLoad } from './$types';
 
 export const load: PageLoad = async ({ url, fetch, data }) => {
 	const view = url.searchParams.get('view');
 	const isDesktop = browser && window.matchMedia('(min-width: 640px)').matches;
-	const density = await fetchDensity(fetch, view, isDesktop);
+
+	// Forward active filters (excluding from/to) so the chart matches the list.
+	const tagOp = url.searchParams.get('tagOp');
+	const filters: DensityFilters = {
+		q: url.searchParams.get('q') ?? undefined,
+		senderId: url.searchParams.get('senderId') ?? undefined,
+		receiverId: url.searchParams.get('receiverId') ?? undefined,
+		tags: url.searchParams.getAll('tag'),
+		tagQ: url.searchParams.get('tagQ') ?? undefined,
+		status: url.searchParams.get('status') ?? undefined,
+		tagOp: tagOp === 'OR' ? 'OR' : 'AND'
+	};
+
+	const density = await fetchDensity(fetch, view, isDesktop, filters);
 	return { ...data, ...density };
 };