Underbook: Hotel Price Comparison for Booking.com & Expedia

Underbook is a free hotel price comparison extension for travelers about to book a hotel online. On a hotel page with your dates at Booking.com, Expedia, Hotels.com, Agoda, or a hotel's own site, it checks the booking sites Google Hotels lists and shows, right on the page, whether another site lists the same stay for less (compared all-in, where the sites report taxes and fees) and whether that lower price names the same room. When it cannot match the room, it says so in one line, so you check before you switch. Under the lower price, a terms line shows whether free cancellation is listed, the room, and the party size. On Chrome and Firefox, the card is shown in 17 languages. You always book on the site you choose.

Optional: a free email alert when the price drops, also for a stay you already booked, checked once a day until free cancellation ends. No account. How it is free: when you open a booking site through Underbook and complete a booking, we may earn an affiliate commission from that site, at no extra cost to you. This never changes which rates we show you or the order we show them.