This largely depends upon the situation you and your spouse are in. As a rule, the less you are able to communicate, settle differences and divide up assets amicably, the longer and more money your divorce is going to cost you. If all goes smoothly and none of the previous factors mentioned are a concern, then you could sever the ties that bind in under 3 weeks, but it can take up to 2 years if it gets ugly. King Henry VIII started a whole religion just so he could get divorced! Lucky for some of his wives that he did. It certainly saved their necks.
In Canada, an uncontested divorce can be wrapped up in 8 to 16 weeks. Usually, the husband and wife must have lived apart for at least a year before divorce can take place.