It depends on the facility, but I agree with Harris. I’ve trained at places where it was 70/30, and I’ve trained at a place that charged their own flat fee per session.
You may also check with other gyms in your area to get an idea of rates–I think this is becoming more common.
It can vary, but the quotes of 30% to 40% taken by the owner are in the ballpark. I’ve paid anywhere from a very low flat fee per month ($100 a month for 10 hours a week access, ended up being about $2.50 per hour) to 40%.
Your negotiating points to help you come up with a fair deal:
How much space / equipment you have to offer
How busy you are at the time the trainer wants to use the facility
Whether you will be posting any of their marketing materials
Whether you can grow each others’ businesses due to differences in offerings.
an additional consideration is that trainers who bring their own clients expose those clients to your facility, and they may start using services that you provide (or recommend you to their friends). A well-established trainer can be a great asset to your facility in which case you can forego a little initial profit for long-term advantage to you.