You aren't looking for a yarn counter, those count rows. What you are looking for is a yardage measure. Using one of those can be tedious as you have to actually run ALL of the yarn through it, necessitating having a ball winder handy, to rewind the skein.
A yarn scale might be a better option...this will tell you how many ounces or grams you have. I purchased a yarn scale and find it comes in handy. When I finish a project, I "weigh" my left over yarn...use my ball winder to wind it into a tighter, center pull ball. Then I place the yarn in a zip lock bag and mark on the bag how many ounces or grams of yarn it contains. Most of these scales give you the option of weighing in either ounces or grams.
A yarn scale might be a better option...this will tell you how many ounces or grams you have. I purchased a yarn scale and find it comes in handy. When I finish a project, I "weigh" my left over yarn...use my ball winder to wind it into a tighter, center pull ball. Then I place the yarn in a zip lock bag and mark on the bag how many ounces or grams of yarn it contains. Most of these scales give you the option of weighing in either ounces or grams.