diff --git a/gcovr-json-diff.py b/gcovr-json-diff.py
new file mode 100755
index 0000000..c3ae122
--- /dev/null
+++ b/gcovr-json-diff.py
@@ -0,0 +1,37 @@
+#! /usr/bin/python3
+
+import json
+import sys
+
+file_a = sys.argv[1]
+json_a = json.load(open(file_a))
+
+file_b = sys.argv[2]
+json_b = json.load(open(file_b))
+
+lines_a = dict()
+
+for file_ in json_a['files']:
+    filename = file_['file']
+
+    covered_lines_a = [ x['line_number'] for x in file_['lines'] if x['count'] > 0]
+
+    lines_a[filename] = covered_lines_a
+
+lines_b = dict()
+
+for file_ in json_b['files']:
+    filename = file_['file']
+
+    covered_lines_b = [ x['line_number'] for x in file_['lines'] if x['count'] > 0]
+
+    lines_b[filename] = covered_lines_b
+
+# see what has been covered in set b and not in a
+for file_ in lines_b:
+    if file_ not in lines_a:
+        print(f'File {file_} only in set {file_b}')
+
+    for line in lines_b[file_]:
+        if not line in lines_a[file_]:
+            print(f'Line {line} in {file_} is only covered in {file_b}')