Kayak is using augmented reality to help travelers measure their luggage. The new bag measurement tool will tell users whether a bag is likely a carry-on or if it should be checked.

Anyone who has been asked to check a bag after they already boarded a flight knows the pain and embarrassment of not having the right-sized luggage. Kayak is addressing this common problem with technology that adds novelty to the “carry it on vs. check it” deliberation.

“There are a lot of AR applications that are fun but this one was designed to be truly useful for travelers,” Kayak chief technology officer Giorgos Zacharia said in a press release.

Kayak’s new AR bag measurement tool, added on Tuesday, is currently available only to iOS users. It was developed during the company’s “SWAT Week,” an annual engineering competition that challenges employees to rapidly design and develop new ideas.

Users can access the tool from the Kayak mobile app. Once opened, users will be prompted to scan the floor to help calibrate measurements, then move the camera around the bag. The AR tool captures the bag’s exact measurements, then recommends whether it qualifies as a carry-on or not.

If the bag is deemed too large for a carry-on, the app automatically compares check baggage fee policies so users know what to expect.

The AR tool continues a trend of Kayak’s try-it-before-you-buy-it-with-technology strategy. In June, Kayak launched a VR app for Google Daydream that lets travelers “visit” a location before booking. The app launched with 360-degree views of Venice and Kathmandu, inviting users to explore the locations with onscreen information or an audio tour.

Kayak continues to invest in technology so it can stand out in the growing travel industry. The brand uses AI to assist its customers through Facebook Messenger, Google and Alexa and says it will continue to invest in a variety of technologies.