Well, by far the most accurate way of measuring your finger for your ring size is to go to a local jewelry store and ask them to measure it for you.
Now size can be given in a few different ways, American Size, European Size, UK Size etc.
Whatever size the jeweler gives you is convertible to a ring size in another country.
Ordering a Ring...
If you are ordering a ring all you need to do is send the size that they give you and we will do the rest.
It is important that the finger that you want to wear the ring is the finger that you have had measured.
Other methods of measuring your finger for ring size...
Now, there are other methods to measure your finger size, however, they are not as accurate as a jeweler.
Some people tie a piece of string or paper around their finger and then make a mark on the paper or string where the finger ends.
This gives you the circumference of the finger. Then the paper or string is measured along side a ruler.
* Again, this method is not the most accurate, however, if done carefully, it can also give you a finger size.