When you fly, every inch of overhead space is precious—and you never want to get to the airport only to realize, too late, that your stuffed suitcase just won’t fit.

The next time you pack your bags, use these AR (augmented reality) travel apps to see exactly how much bin space your plane will have and whether your bag has room to slide in.

Kayak sells tickets for just about every major airline except Southwest, which means its bag sizer works for domestic carriers like American, Delta, and United, and international brands such as Aeromexico, Emirates, and Air France.

To find this feature in Kayak’s app, tap on the flight’s tab; near the bottom of the screen, look for the New Bag Measurement Tool button.

Southwest Airlines doesn’t sell tickets to its flights through third parties, so it has built AR bag sizing into its namesake app.

You can find this feature by tapping your name in the upper left corner of the Southwest app, then tapping Bag Sizer.

Once you’ve packed your bags with these apps, you may never pack without AR again.

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