diff --git a/tools/progress.cpp b/tools/progress.cpp
new file mode 100644
index 0000000..a395ca3
--- /dev/null
+++ b/tools/progress.cpp
@@ -0,0 +1,39 @@
+/*
+ * Copyright 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "progress.hpp"
+
+#include <cstdio>
+
+namespace host_tool
+{
+
+void ProgressStdoutIndicator::updateProgress(std::int64_t bytes)
+{
+    /* Print progress update. */
+    currentBytes += bytes;
+    std::fprintf(stdout, "\rProgress: %.2f%%",
+                 100.0 * currentBytes / totalBytes);
+    std::fflush(stdout);
+}
+
+void ProgressStdoutIndicator::start(std::int64_t bytes)
+{
+    totalBytes = bytes;
+    currentBytes = 0;
+}
+
+} // namespace host_tool