diff --git a/.github/workflows/pull-request-verification.yml b/.github/workflows/pull-request-verification.yml
index b18d7ba..801c7ce 100644
--- a/.github/workflows/pull-request-verification.yml
+++ b/.github/workflows/pull-request-verification.yml
@@ -90,6 +90,9 @@ jobs:
     - name: filter-test
       if: steps.filter.outputs.local != 'true'
       run: exit 1
+    - name: count-test
+      if: steps.filter.outputs.local_count != 1
+      run: exit 1
 
   test-change-type:
     runs-on: ubuntu-latest
diff --git a/README.md b/README.md
index b632837..e623477 100644
--- a/README.md
+++ b/README.md
@@ -147,6 +147,7 @@ For more information see [CHANGELOG](https://github.com/dorny/paths-filter/blob/
 - For each filter it sets output variable named by the filter to the text:
    - `'true'` - if **any** of changed files matches any of filter rules
    - `'false'` - if **none** of changed files matches any of filter rules
+- For each filter it sets output variable with name `${FILTER_NAME}_count` to the count of matching files.
 - If enabled, for each filter it sets output variable with name `${FILTER_NAME}_files`. It will contain list of all files matching the filter.
 - `changes` - JSON array with names of all filters matching any of changed files.
 
diff --git a/dist/index.js b/dist/index.js
index d2b9ab4..35a3f9e 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -4806,6 +4806,7 @@ function exportResults(results, format) {
             core.info('Matching files: none');
         }
         core.setOutput(key, value);
+        core.setOutput(`${key}_count`, files.length);
         if (format !== 'none') {
             const filesValue = serializeExport(files, format);
             core.setOutput(`${key}_files`, filesValue);
diff --git a/src/main.ts b/src/main.ts
index 844b5e4..3e9522f 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -190,6 +190,7 @@ function exportResults(results: FilterResults, format: ExportFormat): void {
     }
 
     core.setOutput(key, value)
+    core.setOutput(`${key}_count`, files.length)
     if (format !== 'none') {
       const filesValue = serializeExport(files, format)
       core.setOutput(`${key}_files`, filesValue)