When selecting a kettlebell to start with, some helpful guidelines that can be considered. I say considered rather than followed absolutely, because each person is unique in terms of age, health, history, experience, goals, and physical attributes.
The only comparison that should be made is between where you are now and where you want to go.
The first and most important consideration is to “First, do no harm”.
This is vitally important, for the doctor, who should never harm the patient. For the trainer, who should never harm the client. For the teacher, who should never harm the student, and for you, who should never harm yourself.
The next consideration is how to get to your goal safely and effectively.
If unsure, air on the side of caution. It’s ok to start out too light, because you can always come back next time and go a bit heavier. It’s a mistake to start too heavy, because if you injure yourself exercising, there may not be a next time. Start slow and build gradually over time.
Consistency is going to be your best friend. It is never what you do in one workout, one week or one month. It’s what you do accumulatively over time that matters most. Refer again to the first rule—do not hurt yourself because nothing interferes with training consistency more than an injury will.
When you understand the right mental outlook and are taking a long-term view to your health and fitness, you are ready for some specific guidelines for selecting the right weight.
Are you a beginner or has it been years since you last followed a consistent exercise habit? If so, go easy. For a women, that might mean a 4 kg (9 lb) kettlebell to begin with. For a man, 12kg (25lb) is a good bet. A more experienced woman can start with 8kg (18lb) and 16kg (35lb) for a more experienced man
If injured and/or pain is associated, you may need to rehabilitate the injured area before starting kettlebell training. If recovering from an injury, choose caution and go light to begin with. See how your body responds before moving up to heavier kettlebells. Always a good idea to have a doctor consult before moving into vigorous training.
Smaller, lighter exercisers will naturally use a lighter weight to begin with and larger heavier users can move up in load accordingly.
As a good rule of thumb, small females may want to start with a 4kg (9lb) and larger females start with a 8kg (18lb).Small males start with 12 (25lb) and larger males with 16kg (35lb).
Progressions typically occur in 2kg to 4kg (4.5 lb to 9 lb) increments.
These guidelines are simply starting points to work from, as is appropriate for your age, experience, and health and fitness level.