diff --git a/src/app/data/data-manager.ts b/src/app/data/data-manager.ts
index 2e2ff583..6532054c 100644
--- a/src/app/data/data-manager.ts
+++ b/src/app/data/data-manager.ts
@@ -39,6 +39,7 @@ import {
   time,
   titlePlural,
 } from '../utils/utils';
+import { isEndingSoon } from '../utils/date-utils';
 import { defaultMapRadius, distance, formatDistance, locationStringToPin, mapPointToPoint } from '../map/map.utils';
 import { GpsCoord, Point, gpsToMap, mapToGps, setReferencePoints } from '../map/geo.utils';
 import { set, get, clear } from 'idb-keyval';
@@ -263,6 +264,7 @@ export class DataManager implements WorkerClass {
     for (const event of this.events) {
       event.old = true;
       event.happening = false;
+      event.endingSoon = false;
       try {
         for (const occurrence of event.occurrence_set) {
           // This makes all events happen today
@@ -274,14 +276,19 @@ export class DataManager implements WorkerClass {
           if (this.allEventsOld) {
             event.old = false;
             event.happening = false;
+            event.endingSoon = false;
             occurrence.old = false;
             occurrence.happening = false;
+            occurrence.endingSoon = false;
             hasLiveEvents = false;
           } else {
-            const isOld = new Date(occurrence.end_time).getTime() - todayTime < 0;
-            const isHappening = !isOld && new Date(occurrence.start_time).getTime() < todayTime;
+            const startTime = new Date(occurrence.start_time).getTime();
+            const endTime = new Date(occurrence.end_time).getTime();
+            const isOld = endTime - todayTime < 0;
+            const isHappening = !isOld && startTime < todayTime;
             occurrence.old = isOld;
             occurrence.happening = isHappening;
+            occurrence.endingSoon = isHappening && isEndingSoon(startTime, endTime, todayTime);
             if (!occurrence.old) {
               event.old = false;
               hasLiveEvents = true;
@@ -289,6 +296,9 @@ export class DataManager implements WorkerClass {
             if (occurrence.happening) {
               event.happening = true;
             }
+            if (occurrence.endingSoon) {
+              event.endingSoon = true;
+            }
           }
         }
       } catch (err) {
diff --git a/src/app/data/models.ts b/src/app/data/models.ts
index 53c5badf..7b6cdb65 100644
--- a/src/app/data/models.ts
+++ b/src/app/data/models.ts
@@ -20,6 +20,7 @@ export interface Event {
   longTimeString: string; // Calculated
   old: boolean; // Calculated (whether the event has already passed)
   happening: boolean; // Calculated (whether the event is happening now)
+  endingSoon?: boolean; // Calculated (whether a current occurrence has less than 25% of its duration left)
   group?: string; // Calculated (grouping for favorites)
   distance: number; // Calculated
   distanceInfo: string; // Calculated
@@ -74,6 +75,7 @@ export interface OccurrenceSet {
   start_time: string;
   old: boolean; // Calculated
   happening: boolean; // Calculated (whether the event is happening now)
+  endingSoon?: boolean; // Calculated (whether this occurrence has less than 25% of its duration left)
   longTimeString: string; // Calculated
   star?: boolean;
 }
diff --git a/src/app/event/event.component.html b/src/app/event/event.component.html
index d59e08da..dc918296 100644
--- a/src/app/event/event.component.html
+++ b/src/app/event/event.component.html
@@ -15,7 +15,9 @@ <h1 style="display: flex">
       <app-cached-img class="image" [alt]="event().title" [src]="event().imageUrl" />
     </div>
   }
-  @if (event().happening) {
+  @if (event().endingSoon) {
+    <p class="badge">ENDING SOON</p>
+  } @else if (event().happening) {
     <p class="badge">NOW</p>
   }
   <ion-card-header>
diff --git a/src/app/event/event.page.html b/src/app/event/event.page.html
index 237223a5..fdc19e8f 100644
--- a/src/app/event/event.page.html
+++ b/src/app/event/event.page.html
@@ -82,7 +82,9 @@ <h1 class="page-focus">{{event.title}}</h1>
     <ion-item (click)="toggleStar(occurrence)">
       <ion-icon aria-hidden="true" name="time-outline" slot="start"></ion-icon>
       <ion-label>{{occurrence.longTimeString}}</ion-label>
-      @if (occurrence.happening) {
+      @if (occurrence.endingSoon) {
+      <app-badge>Ending Soon</app-badge>
+      } @else if (occurrence.happening) {
       <app-badge>Now</app-badge>
       } @if (!occurrence.happening) {
       <ion-button aria-label="Make this event a favorite" color="primary" fill="clear" slot="end">
diff --git a/src/app/events-card/events-card.component.html b/src/app/events-card/events-card.component.html
index 45d77cfb..9489fa81 100644
--- a/src/app/events-card/events-card.component.html
+++ b/src/app/events-card/events-card.component.html
@@ -10,7 +10,9 @@
         [routerLink]="'/event/' + event.uid + '+' + 'Home'"
         [lines]="items()[index].lines"
       >
-        @if (event.happening) {
+        @if (event.endingSoon) {
+          <p class="badge">ENDING SOON</p>
+        } @else if (event.happening) {
           <p class="badge">NOW</p>
         }
         <span slot="start">{{ items()[index].time }}</span>
diff --git a/src/app/utils/date-utils.test.ts b/src/app/utils/date-utils.test.ts
index 67b58ab6..971abcbe 100644
--- a/src/app/utils/date-utils.test.ts
+++ b/src/app/utils/date-utils.test.ts
@@ -1,5 +1,5 @@
 import { describe, it, expect } from 'vitest';
-import { daysHighlighted, getTimeInTimeZone, toDate, getTimeZoneOffsetHours } from './date-utils';
+import { daysHighlighted, getTimeInTimeZone, isEndingSoon, toDate, getTimeZoneOffsetHours } from './date-utils';
 
 describe('date-utils', () => {
   describe('toDate', () => {
@@ -121,6 +121,35 @@ describe('date-utils', () => {
     });
   });
 
+  describe('isEndingSoon', () => {
+    const start = new Date('2024-08-28T13:00:00-07:00').getTime();
+    const end = new Date('2024-08-28T17:00:00-07:00').getTime();
+
+    it('is true when less than 25% of a running event remains', () => {
+      const now = new Date('2024-08-28T16:30:00-07:00').getTime();
+      expect(isEndingSoon(start, end, now)).toBe(true);
+    });
+
+    it('is false at exactly 25% remaining and true immediately after', () => {
+      const quarterLeft = new Date('2024-08-28T16:00:00-07:00').getTime();
+      const underQuarter = new Date('2024-08-28T16:01:00-07:00').getTime();
+      expect(isEndingSoon(start, end, quarterLeft)).toBe(false);
+      expect(isEndingSoon(start, end, underQuarter)).toBe(true);
+    });
+
+    it('is false before the event starts and once it ends', () => {
+      expect(isEndingSoon(start, end, start - 1)).toBe(false);
+      expect(isEndingSoon(start, end, end)).toBe(false);
+      expect(isEndingSoon(start, end, end + 1)).toBe(false);
+    });
+
+    it('rejects invalid and non-positive durations', () => {
+      expect(isEndingSoon(start, start, start)).toBe(false);
+      expect(isEndingSoon(end, start, start)).toBe(false);
+      expect(isEndingSoon(Number.NaN, end, start)).toBe(false);
+    });
+  });
+
   describe('daysHighlighted', () => {
     it('should highlight all days for Burning Man 2024 event week', () => {
       // Real scenario: Burning Man 2024 dates (Aug 25 - Sept 2)
diff --git a/src/app/utils/date-utils.ts b/src/app/utils/date-utils.ts
index 9f1b818e..e67a1d4b 100644
--- a/src/app/utils/date-utils.ts
+++ b/src/app/utils/date-utils.ts
@@ -28,6 +28,22 @@ export function toDate(d: string | undefined): Date | undefined {
   return new Date(d);
 }
 
+export function isEndingSoon(startTime: number, endTime: number, nowTime = Date.now()): boolean {
+  const duration = endTime - startTime;
+  if (
+    !Number.isFinite(startTime) ||
+    !Number.isFinite(endTime) ||
+    !Number.isFinite(nowTime) ||
+    duration <= 0 ||
+    nowTime <= startTime ||
+    nowTime >= endTime
+  ) {
+    return false;
+  }
+
+  return endTime - nowTime < duration * 0.25;
+}
+
 export function getTimeZoneOffsetHours(timeZone: string): number {
   const date = new Date();
   const timeZoneString = new Intl.DateTimeFormat('en-US', { timeZone, timeZoneName: 'longOffset' })