It is nearly impossible to predict the exact cost of a divorce. There are many factors involved in divorce that determine the cost. Marriages with children, for example, tend to take longer as parents figure out details concerning important aspects of their children's lives, such as child support and custody.
Even marriages with no children may have many contested issues that need to be worked out between parties, such as spousal maintenance and property valuations. The longer it takes for the opposing parties to agree on a settlement, the more expensive the divorce will be. It is in the best interests of everyone involved to find agreements on as many issues as possible.