Top five most expensive US cities for room service

(iStock)

If you're planning a trip to Las Vegas, better pack a lunch.

The average cost of room service in Las Vegas is a whopping $68, making it the most expensive place to order room service in the country, according to a recent survey.

Researchers from TripAdvisor compared the cost of "in-room amenities" from hotels in 15 cities across the country. They added up the price of ordering a club sandwich through room service, getting a shirt dry cleaned through the hotel's cleaning service, and taking water, peanuts, vodka and a can of soda from the mini fridge.

The results, announced yesterday, revealed that the cost of room service has increased nationwide, with $55 being the average total cost for room service in U.S. cities, $3 more expensive than last year.

If you're looking to avoid dishing out serious cash for in-room amenities, here are the survey's top five most expensive U.S. cities for room service:

1. Las Vegas: $68.01
2. New York City: $67.83
3. Washington, D.C.: $61.66
4. Los Angeles: $60.67
5. Honolulu: $59.92

If you can't live without room service, TripAdvisor recommends visiting Denver, where the average cost for their order was $41. Seattle was the next in line with a $42 total, and Minneapolis cost $46.