Free Chrome extension
Most price-comparison tools quote you a cheaper number — then quietly hand you a smaller room or a non-refundable rate. Underbook checks if your room is cheaper somewhere else and shows the room type and cancellation terms, side by side, so you're comparing the same thing. Free, and you always book where you choose.
Free · no account needed · we never see your payment info.
Three steps, all inside your own browser. Nothing to sign up for.
Search a hotel on the site you already use. Underbook stays out of the way until there's a reason to speak up.
Underbook checks other booking sites for the same hotel, same dates, and same room — quietly, in the background.
If a cheaper rate exists, you see the room name and cancellation terms next to what you were about to book. You choose where to book.
A lower price is only a deal if it's the same room on the same terms. Booking sites are full of near-matches: a "city view" swapped for a "standard," a fully-refundable rate quietly replaced with a non-refundable one, a resort fee that only appears at checkout. A comparison that ignores those differences isn't saving you money — it's changing your booking.
Underbook's whole job is to make the comparison honest. It surfaces the room type and cancellation policy from each site so you can confirm they line up. When it can't confirm the two rooms are identical, it says so plainly and shows you both — it never pretends a lookalike is the same room to win a click.
What Underbook does
What it never does
The trap is comparing a cheaper rate that's really a different room or a non-refundable version. Underbook lines up the room name and cancellation policy from each site so you can confirm it's the same room before you book. When it can't confirm the match, it tells you plainly and shows both.
Lesser-known booking sites buy rooms through different wholesale channels and spend less on advertising, so their listed rates are sometimes lower. Not always the identical room, though — which is exactly why Underbook shows you the room type and cancellation terms to compare before you book.
No. Underbook is a free Chrome extension. If you book through a site it surfaces, it may earn a small commission from that site — you pay nothing extra, and it shows the lower rate even when its commission would be smaller.
The check runs in your own browser. Underbook never sees or stores your payment details, booking happens on the site you choose, and it doesn't sell your data. Read the privacy policy →
Free hotel price comparison for the exact room you're booking. We never see your payment, and you always book where you choose.
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