Thread: Smith Machine vs Free Bench Press

There's no formula because your technique determines the force loss specific to you, and may vary even based on the weight.

Assuming you have theoretically perfect technique in both, the Smith will be lower because of increased resistance in the sliding mechanism. In practice, this is impossible because no one benches without some degree of lateral movement, nor force loss in the rack.

To be honest, I found myself being able to lift more on a Smith Machine than free weights. I know there are studies saying opposite but this is just from personal experience.

But I have only used it for squats (now use squat rack).