เว็บคำนวณ MgR/I
https://impactingtennis.com/education-tools/mgr-i/
Swing Weight Calculator
http://twu.tennis-warehouse.com/learning_center/swingweight_calc.php
http://www.liquid12.nl/swcalc/index-en.php
https://impactingtennis.com/education-tools/swingweight/