Barbell ↔ Machine Conversion
There is no reliable general conversion between a barbell and a machine. This gives you a starting number so your first set is not a wild guess, and nothing more.
Your results
Machines vary so much that this figure could be 50% out in either direction. Use it to pick a first warm-up weight, then let the set tell you the truth.
Why machine numbers do not transfer
A barbell load is unambiguous — 100 kg is 100 kg regardless of the gym. A machine load is not, for several reasons that stack up:
- Leverage. Lever machines change the effective resistance through the range depending on where the pivot sits.
- Pulley ratio. A cable machine with a 2:1 ratio delivers half the stack weight to your hands. Ratios vary and are rarely labelled.
- Frame support. On a leg press the sled carries some of the load and the angle changes the vector, which is why leg press numbers are roughly double squat numbers — and 'roughly' covers a very wide range.
- Seat and pad position. Changes the moment arm on the same machine.
- Friction and maintenance. Genuinely measurable on older equipment.
Two leg presses in the same gym can differ by 50%. Two in different gyms can differ by more.
What to do instead
- Do one light set on the machine and see how it feels.
- Work up in a few steps. You will find your working weight in two or three sets.
- Record the machine and the setting. Seat position, pad height, which machine in which gym. Then your own numbers become comparable over time, which is the only comparison that matters.
- Do not compare machine numbers between gyms. They are not the same measurement.
Common questions
Why is my leg press so much higher than my squat?
The sled carries part of the load, the angle changes the force vector, and you are not stabilising a bar. Two to three times your squat is normal and means little.
Is there a proper barbell-to-machine conversion?
No. Machines differ by leverage, pulley ratio, frame support and setup. Any single conversion factor is a guess.
Can I compare machine weights between gyms?
No. Track your own numbers on a specific machine instead.
Are machines worse than free weights?
No — for hypertrophy they work well and carry less skill and risk. They do less for balance and trunk strength.
Related calculators
Track the numbers, not just calculate them
MyFitsy stores your weight, measurements and every session, so the figures above become a trend instead of a one-off.
