Why does my hotel booking price change over time?

I have recently booked a few hotels for my trip to Japan next year. I booked some through Agoda and some through Booking.com

I have seen that the Agoda price in GBP has not changed, I am assuming it is a fixed price and will be like that until I pay. However the hotels booked with Booking.com have surged up in price and have only now recently started to go down again. During this time the Yen price has not changed on both websites.

I had presumed this was down to the way sterling has been performing the last few months or so. However, it seems that the hotel I booked for Tokyo had actually gone down in price, which disproves my theory in a way.

My question is: Is there an algorithm used here when calculating the current price? Is there a specific time I should pay for the hotels (i.e. when they're at the lowest in price)? And should I book these hotels with Agoda instead so that the price stays fixed?

If anyone would like the actual values for my booking.com bookings:

Best Answer

To add to the answers above, from my experience, those two sites (Agoda and Booking) work differently for hotels in most of Asia. Agoda charges you in full at the moment you make the reservation, and issues you a voucher you present to the hotel. No further payment is due, and you don't even need to give them your credit card (although some would still insist for "a deposit" but generally they prefer cash) Thus the price Agoda charges you in this case cannot change at all.

(Still in many cases I was still able to find later the same hotel for the same dates on Agoda cheaper; canceled the reservation and got the new price. If you want to do this, make sure you get free cancellation; Agoda recently started charging a cancellation fee on some properties, even if the hotel otherwise comes with free cancellation).

Booking.com makes a true reservation - i.e. they submit your data and CC to hotel, which holds a room for you. You're not charged anything until arrival, and if the room is charged in currency different from yours, the amount you would have to pay may change depending on the exchange rate. Note that the room may be quoted to you in any currency, but there will always be note in small print that the actual amount you pay would depend on the exchange rate later.