diff --git a/include/tinyfk.hpp b/include/tinyfk.hpp
index 37deb91..e71910f 100644
--- a/include/tinyfk.hpp
+++ b/include/tinyfk.hpp
@@ -69,6 +69,7 @@ class KinematicModel {
 
   RelevancePredicateTable rptable_;
   int num_dof_;
+  double total_mass_;
 
   mutable SizedStack<LinkIdAndTransform> transform_stack_;
   mutable SizedCache<Transform> transform_cache_;
diff --git a/src/tinyfk.cpp b/src/tinyfk.cpp
index 2955b34..313ca8c 100644
--- a/src/tinyfk.cpp
+++ b/src/tinyfk.cpp
@@ -34,6 +34,14 @@ KinematicModel::KinematicModel(const std::string &xml_string) {
   }
   size_t N_link = lid; // starting from 0 and finally ++ increment, so it'S ok
 
+  // compute total mass
+  double total_mass = 0.0;
+  for (const auto &link : links) {
+    if (link->inertial != nullptr) {
+      total_mass += link->inertial->mass;
+    }
+  }
+
   // construct joints and joint_ids, and numbering joint id
   std::vector<urdf::JointSharedPtr> joints;
   std::unordered_map<std::string, int> joint_ids;
@@ -74,6 +82,7 @@ KinematicModel::KinematicModel(const std::string &xml_string) {
   joints_ = joints;
   joint_ids_ = joint_ids;
   num_dof_ = num_dof;
+  total_mass_ = total_mass;
   joint_angles_ = joint_angles;
 
   // add COM of each link as new link