The company on Thursday announced it was increasing the cost of a classic membership from $10 per month to $15 per month, effective this summer. That could be the motivation some fence-sitters need to join, though, as any member who has the $10 plan when the rate hike goes into effect will continue to pay $10 per month “for the duration of their membership,” the company said.

For now, no plans are in place to increase the price of the Black Card membership, which currently costs $25 per month and lets members bring a guest and access any Planet Fitness location. The company, however, did say it will start testing higher fees for that membership in some locations this summer, which could portend a future across-the-board increase.

The price increase comes as the company reported weaker-than-expected revenues in the first quarter. Planet Fitness also cut its guidance for the year. Officials warned that even with the 50% price hike on the classic membership, it could “take some time” before the company begins to see benefits, since it will honor the $10 rate for existing customers.

Planet Fitness has long used the $10 rate as a lure to get people into its gyms who might have been intimidated by more expensive options at competitors, which can charge up to $100 per month or more, depending on offerings.

By offering a monthly rate that’s about the same price as a single value meal at a fast-food restaurant, the company has been able to retain many of those members, who often don’t cancel their membership, even if they don’t go for months at a time.

Planet Fitness last raised rates on its basic plan in 1998.