diff --git a/src/queries.ts b/src/queries.ts
index 406a3431..f95c780e 100644
--- a/src/queries.ts
+++ b/src/queries.ts
@@ -245,11 +245,21 @@ const browser_appnames: Record<string, string[]> = {
 };
 
 // Returns a list of (browserName, bucketId) pairs for found browser buckets
+function browserBucketMatches(bucketId: string, browserName: string): boolean {
+  return _.includes(bucketId, browserName);
+}
+
+function browserBucketExists(browserbuckets: string[], browserName: string): boolean {
+  return _.some(browserbuckets, bucket_id => browserBucketMatches(bucket_id, browserName));
+}
+
 function browsersWithBuckets(browserbuckets: string[]): [string, string][] {
   const browsername_to_bucketid: [string, string | undefined][] = _.map(
     Object.keys(browser_appnames),
     browserName => {
-      const bucketId = _.find(browserbuckets, bucket_id => _.includes(bucket_id, browserName));
+      const bucketId = _.find(browserbuckets, bucket_id =>
+        browserBucketMatches(bucket_id, browserName)
+      );
       return [browserName, bucketId];
     }
   );
@@ -262,8 +272,11 @@ function browsersWithBuckets(browserbuckets: string[]): [string, string][] {
 // Used with filter_keyvals_regex in addition to the exact names in browser_appnames.
 // The full set of historical app names these patterns replace is documented in the unit tests.
 // See: test/unit/queries.test.node.ts, https://github.com/ActivityWatch/aw-webui/issues/749
+const chrome_appname_regex = '(?i)^(google[-_ ]?chrome|chrome|chromium)';
+const chrome_appname_regex_with_helium = '(?i)^(google[-_ ]?chrome|chrome|chromium|helium)';
+
 export const browser_appname_regex: Record<string, string> = {
-  chrome: '(?i)^(google[-_ ]?chrome|chrome|chromium)',
+  chrome: chrome_appname_regex,
   firefox: '(?i)(firefox|librewolf|waterfox|nightly)',
   opera: '(?i)(opera)',
   brave: '(?i)(brave)',
@@ -277,6 +290,15 @@ export const browser_appname_regex: Record<string, string> = {
   helium: '(?i)(helium)',
 };
 
+function browserAppnameRegex(browserName: string, browserbuckets: string[]): string | undefined {
+  // Helium can use the Chrome Web Store extension, which emits aw-watcher-web-chrome buckets.
+  // Only match Helium there when no dedicated Helium bucket exists, to avoid double-counting.
+  if (browserName === 'chrome' && !browserBucketExists(browserbuckets, 'helium')) {
+    return chrome_appname_regex_with_helium;
+  }
+  return browser_appname_regex[browserName];
+}
+
 // Returns a list of active browser events (where the browser was the active window) from all browser buckets
 function browserEvents(params: DesktopQueryParams): string {
   let code = `
@@ -289,7 +311,7 @@ function browserEvents(params: DesktopQueryParams): string {
        window_${browserName} = filter_keyvals(events, "app", ${browser_appnames_str});`;
 
     // Add regex-based matching to cover case/spacing/versioning variants (e.g., Firefox.exe, firefox-esr-esr140)
-    const pattern = browser_appname_regex[browserName];
+    const pattern = browserAppnameRegex(browserName, params.bid_browsers);
     if (pattern) {
       code += `
        window_${browserName}_re = filter_keyvals_regex(events, "app", ${JSON.stringify(pattern)});
diff --git a/test/unit/queries.test.node.ts b/test/unit/queries.test.node.ts
index 19dab25f..722aca7c 100644
--- a/test/unit/queries.test.node.ts
+++ b/test/unit/queries.test.node.ts
@@ -53,7 +53,7 @@
  *             (Flatpak app ID retained: 'one.ablaze.floorp')
  */
 
-import { browser_appname_regex } from '~/queries';
+import { browser_appname_regex, fullDesktopQuery } from '~/queries';
 
 // Convert ActivityWatch (?i) patterns to JS RegExp with i flag for testing.
 // AW server uses Python-style (?i) inline flag; JS uses RegExp 'i' flag instead.
@@ -62,6 +62,18 @@ function toRegex(pattern: string): RegExp {
   return new RegExp(stripped, 'i');
 }
 
+function browserQueryForBuckets(bid_browsers: string[]): string {
+  return fullDesktopQuery({
+    bid_window: 'aw-watcher-window_testhost',
+    bid_afk: 'aw-watcher-afk_testhost',
+    bid_browsers,
+    filter_afk: true,
+    categories: [],
+    filter_categories: [],
+    include_audible: false,
+  }).join('\n');
+}
+
 describe('browser_appname_regex', () => {
   test('chrome pattern matches all known Chrome/Chromium app names', () => {
     const re = toRegex(browser_appname_regex.chrome);
@@ -95,6 +107,29 @@ describe('browser_appname_regex', () => {
     expect(re.test('Electron')).toBe(false);
   });
 
+  test('chrome web watcher bucket matches Helium when there is no Helium bucket', () => {
+    const query = browserQueryForBuckets(['aw-watcher-web-chrome_testhost']);
+    expect(query).toContain(
+      'window_chrome_re = filter_keyvals_regex(events, "app", "(?i)^(google[-_ ]?chrome|chrome|chromium|helium)")'
+    );
+  });
+
+  test('chrome web watcher bucket does not match Helium when a Helium bucket exists', () => {
+    const query = browserQueryForBuckets([
+      'aw-watcher-web-chrome_testhost',
+      'aw-watcher-web-helium_testhost',
+    ]);
+    expect(query).toContain(
+      'window_chrome_re = filter_keyvals_regex(events, "app", "(?i)^(google[-_ ]?chrome|chrome|chromium)")'
+    );
+    expect(query).toContain(
+      'window_helium_re = filter_keyvals_regex(events, "app", "(?i)(helium)")'
+    );
+    expect(query).not.toContain(
+      'window_chrome_re = filter_keyvals_regex(events, "app", "(?i)^(google[-_ ]?chrome|chrome|chromium|helium)")'
+    );
+  });
+
   test('firefox pattern matches all known Firefox/LibreWolf/Waterfox app names', () => {
     const re = toRegex(browser_appname_regex.firefox);
     // Every entry from the old exact-match list