When I'm searching on Uber's official site for an estimate from airport to hotel it's giving me a price (the cheapest rate) of $20-24, but when I also do this search with Ride Guru its giving me a rate or estimate of $13.09? which is correct?
The Guru Take
You are hitting surge, covered up as "upfront pricing."
Despite Uber's app not indicating it, you are likely hitting an instance of surge pricing, Uber's demand-based pricing. Uber calls this concept the "upfront pricing," where they would quote you a price that is higher than the rates posted on their website, that are based on distance and duration.
The catch is that Uber does not tell you about the surge multiplier. What you see is what you get.
Uber claims this simplifies the fares as there is "no math and no surprises", but this has drawn criticism for the fares not aligning with posted rates as well as drivers not getting paid for the price paid. (they only get paid for the normal fare based on posted rates) Hence the market is calling this Uber's attepmt to overcharge the consumers and underpay the drivers.
If you notice are noticeable fare differences between RideGuru and Uber's estimates, this is usually the cause. You may want to go back to the price comparison list, and potentially pick an alternate ride at a lower cost.
Here's a quote from Uber:
Upfront fares are calculated using the expected time and distance of the trip and local traffic, as well as how many riders and nearby drivers are using Uber at that moment. And when fares go up due to increased demand, instead of surge lightning bolts and pop-up screens, riders are given the actual fare before they request their ride. There’s no complicated math and no surprises: passengers can just sit back and enjoy the ride.