diff --git a/src/serial_bridge_index.cpp b/src/serial_bridge_index.cpp
index 81b0d7d..cbc00ee 100644
--- a/src/serial_bridge_index.cpp
+++ b/src/serial_bridge_index.cpp
@@ -327,6 +327,28 @@ string serial_bridge::estimated_tx_network_fee(const string &args_string)
 	//
 	return ret_json_from_root(root);
 }
+string serial_bridge::estimate_rct_tx_size(const string &args_string)
+{
+	boost::property_tree::ptree json_root;
+	if (!parsed_json_root(args_string, json_root)) {
+		// it will already have thrown an exception
+		return error_ret_json_from_message("Invalid JSON");
+	}
+	std::size_t size = monero_fee_utils::estimate_rct_tx_size(
+		stoul(json_root.get<string>("n_inputs")),
+		stoul(json_root.get<string>("mixin")),
+		stoul(json_root.get<string>("n_outputs")),
+		stoul(json_root.get<string>("extra_size")),
+		json_root.get<bool>("bulletproof")
+	);
+	std::ostringstream o;
+	o << size;
+	//
+	boost::property_tree::ptree root;
+	root.put(ret_json_key__generic_retVal(), o.str());
+	//
+	return ret_json_from_root(root);
+}
 //
 string serial_bridge::generate_key_image(const string &args_string)
 {
diff --git a/src/serial_bridge_index.hpp b/src/serial_bridge_index.hpp
index 70d4908..711f14f 100644
--- a/src/serial_bridge_index.hpp
+++ b/src/serial_bridge_index.hpp
@@ -62,6 +62,7 @@ namespace serial_bridge
 	string validate_components_for_login(const string &args_string);
 	//
 	string estimated_tx_network_fee(const string &args_string);
+	string estimate_rct_tx_size(const string &args_string);
 	//
 	string generate_key_image(const string &args_string);
 	//
diff --git a/test/test_all.cpp b/test/test_all.cpp
index 9f23299..31d3ce3 100644
--- a/test/test_all.cpp
+++ b/test/test_all.cpp
@@ -865,6 +865,33 @@ BOOST_AUTO_TEST_CASE(bridged__estimated_tx_network_fee)
 	BOOST_REQUIRE(fee == 330047330);
 	cout << "bridged__estimated_tx_network_fee: " << fee << endl;
 }
+BOOST_AUTO_TEST_CASE(bridged__estimate_rct_tx_size)
+{
+	using namespace serial_bridge;
+	//
+	boost::property_tree::ptree root;
+	root.put("n_inputs", "1");
+	root.put("mixin", "10");
+	root.put("n_outputs", "2");
+	root.put("extra_size", "0");
+	root.put("bulletproof", "true");
+	//
+	auto ret_string = serial_bridge::estimate_rct_tx_size(args_string_from_root(root));
+	stringstream ret_stream;
+	ret_stream << ret_string;
+	boost::property_tree::ptree ret_tree;
+	boost::property_tree::read_json(ret_stream, ret_tree);
+	optional<string> err_string = ret_tree.get_optional<string>(ret_json_key__any__err_msg());
+	if (err_string != none) {
+		BOOST_REQUIRE_MESSAGE(false, *err_string);
+	}
+	optional<string> size_string = ret_tree.get_optional<string>(ret_json_key__generic_retVal());
+	BOOST_REQUIRE(size_string != none);
+	BOOST_REQUIRE((*size_string).size() > 0);
+	size_t size = stoul(*size_string);
+	BOOST_REQUIRE(size == 1848);
+	cout << "bridged__estimate_rct_tx_size: " << size << endl;
+}
 BOOST_AUTO_TEST_CASE(bridged__generate_key_image)
 {
 	using namespace serial_bridge;