diff --git a/aosp/cow_converter.cc b/aosp/cow_converter.cc
index 3d314c4..f4ac5b0 100644
--- a/aosp/cow_converter.cc
+++ b/aosp/cow_converter.cc
@@ -124,11 +124,38 @@
     return 5;
   }
 
+  size_t estimated_total_cow_size = 0;
+  size_t actual_total_cow_size = 0;
+
   for (const auto& partition : manifest.partitions()) {
+    if (partition.estimate_cow_size() == 0) {
+      continue;
+    }
     LOG(INFO) << partition.partition_name();
     if (!ProcessPartition(partition, images_dir, manifest.block_size())) {
       return 6;
     }
+    base::FilePath img_dir{images_dir};
+    const auto output_cow =
+        img_dir.Append(partition.partition_name() + ".cow").value();
+    const auto actual_cow_size =
+        chromeos_update_engine::utils::FileSize(output_cow);
+    LOG(INFO) << partition.partition_name()
+              << ": estimated COW size is: " << partition.estimate_cow_size()
+              << ", actual COW size is: " << actual_cow_size
+              << ", estimated COW size is "
+              << (actual_cow_size - partition.estimate_cow_size()) * 100.0f /
+                     actual_cow_size
+              << "% smaller";
+    estimated_total_cow_size += partition.estimate_cow_size();
+    actual_total_cow_size += actual_cow_size;
   }
+
+  LOG(INFO) << "Total estimated COW size is: " << estimated_total_cow_size
+            << ", Total actual COW size is: " << actual_total_cow_size
+            << ", estimated COW size is "
+            << (actual_total_cow_size - estimated_total_cow_size) * 100.0f /
+                   actual_total_cow_size
+            << "% smaller";
   return 0;
 }