There is no way to know your bone mass without measuring. To do this at home, you can use a Tanita body composition monitor. Our bathroom scales send a very small electric current through your body.
Since bones, fat, muscle and other tissue all conduct electricity at a different rate, the scale can then calculate your bone mass. Of course, there are more metrics you should know to find out if you are healthy.
A Tanita weighing scale can also tell you your muscle mass, visceral fat percentage, body fat percentage and body water percentage. It can then interpret these data to assess your health and letting you know what you should work on.