diff --git a/monero_utils/MyMoneroCoreBridge.js b/monero_utils/MyMoneroCoreBridge.js
index 9b3a25d..6f89ee0 100644
--- a/monero_utils/MyMoneroCoreBridge.js
+++ b/monero_utils/MyMoneroCoreBridge.js
@@ -476,6 +476,24 @@ class MyMoneroCoreBridge
 		}
 		return ret.retVal; // this is a string - pass it to new JSBigInt(…)
 	}
+	estimate_rct_tx_size(n_inputs, mixin, n_outputs, extra_size, bulletproof)
+	{
+		const args =
+		{
+			n_inputs,
+			mixin,
+			n_outputs,
+			extra_size,
+			bulletproof
+		};
+		const args_str = JSON.stringify(args);
+		const ret_string = this.Module.estimate_rct_tx_size(args_str);
+		const ret = JSON.parse(ret_string);
+		if (typeof ret.err_msg !== 'undefined' && ret.err_msg) {
+			return { err_msg: ret.err_msg }
+		}
+		return parseInt(ret.retVal, 10);
+	}
 	//
 	// Send
 	__key_for_fromCpp__send_funds__get_unspent_outs(task_id)
@@ -774,4 +792,4 @@ module.exports = function(options)
 			}, 1) 
 		}
 	});
-};
\ No newline at end of file
+};
diff --git a/src/index.cpp b/src/index.cpp
index 58187ff..c78c9d9 100644
--- a/src/index.cpp
+++ b/src/index.cpp
@@ -57,6 +57,7 @@ EMSCRIPTEN_BINDINGS(my_module)
     emscripten::function("address_and_keys_from_seed", &serial_bridge::address_and_keys_from_seed);
     //
     emscripten::function("estimated_tx_network_fee", &serial_bridge::estimated_tx_network_fee);
+    emscripten::function("estimate_rct_tx_size", &serial_bridge::estimate_rct_tx_size);
     //
     emscripten::function("generate_key_image", &serial_bridge::generate_key_image);
     emscripten::function("generate_key_derivation", &serial_bridge::generate_key_derivation);
diff --git a/tests/MyMoneroCoreCpp.node.js b/tests/MyMoneroCoreCpp.node.js
index ee84fe9..4062a2b 100644
--- a/tests/MyMoneroCoreCpp.node.js
+++ b/tests/MyMoneroCoreCpp.node.js
@@ -133,6 +133,13 @@ function tests(Module)
 		console.timeEnd("estimated_tx_network_fee")
 		console.log("estimated_tx_network_fee ret", ret_string)
 	}
+	{
+		console.time("estimate_rct_tx_size")
+		const args_str = '{"n_inputs":1,"mixin":10,"n_outputs":2,"extra_size":0,"bulletproof":true}'
+		const ret_string = Module.estimate_rct_tx_size(args_str)
+		console.timeEnd("estimate_rct_tx_size")
+		console.log("estimate_rct_tx_size ret", ret_string)
+	}
 	{
 		console.time("generate_key_image")
 		const args_str = '{"sec_viewKey_string":"7bea1907940afdd480eff7c4bcadb478a0fbb626df9e3ed74ae801e18f53e104","sec_spendKey_string":"4e6d43cd03812b803c6f3206689f5fcc910005fc7e91d50d79b0776dbefcd803","pub_spendKey_string":"3eb884d3440d71326e27cc07a861b873e72abd339feb654660c36a008a0028b3","tx_pub_key":"fc7f85bf64c6e4f6aa612dbc8ddb1bb77a9283656e9c2b9e777c9519798622b2","out_index":"0"}'