If only there was a free app to say "I do."

A survey of nearly 18,000 brides found couples are shelling out more than ever when it comes to their special day, and mainly use their phones to do the planning.

The research, completed by wedding planning website TheKnot, finds the average cost of a wedding in the U.S. as of 2015 is $32,641, an average increase of $5,500 since 2009. Depending on the location of the wedding, the number can be considerably higher. Manhattan tops the list of most expensive with an average cost of $82,299. 

The cost of a reception venue, ceremony site and reception band were the three components that saw the biggest price increase since 2009, driving overall wedding costs up.

Eighty-nine percent of couples say they used a mobile device to plan their wedding in some way. From registering for gifts to looking up vendors, the majority of couples opt to use mobile devices over desktops or tablets. 

More than half of brides (58%) use their phones to look at wedding dresses, and the same percentage look up and manage their vendor information using their phones. This means wedding companies can benefit from having streamlined mobile platforms.

Surprisingly though, with all the use of technology to plan their wedding, only 16% of couples use online-only RSVPs. 

While couples are inviting fewer people, the cost per guest has increased significantly since 2009. Five years ago the average number of guests was 149, and each guest cost an average of $194. In 2015, 139 guests was the average but each cost $237.

The wedding tradition of "the family of the bride pays" lives on: 44% of the overall wedding budget comes from the bride's parents; 43% comes from the bride and groom; the other 12% comes from the groom's parents; 1% comes from "other."

In 2015 only 12% of couples paid for the entire event themselves, but only 9% didn't contribute financially at all. 

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