Hi, if you have a local supplier, the easiest way to match it is bring the bolt in and match it. I forget the size myself, but it is a standard metric size, nothing unusual. Also, the big box home improvement stores carry metric bolts. The bolt diameter is easy to compare visually, the thread pitch can be determinecd by placing the threads on your bolt and the store's bolt together. Most metric bolts sizes have two thread pitches available and some have three.