When you're choosing a piece of cardio equipment to work out indoors, you need to analyze what works best with your body, what (if any) other equipment you need, how it will serve your goal, and any other personal preferences you may have. Every piece of equipment is designed in a specific way and has its pros and cons.
When you are choosing a stationary bike vs. treadmill, here are some differences to consider. Running on a treadmill tends to burn a lot of calories, and it is an intense workout. Many treadmills offer variable speeds and inclines that you can set according to your needs. But running on the treadmill also carries a higher risk of injury to the knees, back, and joints. It can also be tempting to "cheat" by holding onto the handles for support. On the other hand, a stationary bike may not burn as many calories but provides good results, strengthening the body and building endurance. So, it is essential to choose the equipment according to your needs.