Measuring arrows can sound like a pretty straightforward ordeal. Break out the tape measure (or tailor's tape, your choice), and see how long the arrow is. Unfortunately, as with most things in archery, it isn't quite that simple.
Now, we aren't saying that measuring an arrow requires textbooks worth of knowledge and know-how, but you don't want to get your arrows cut wrong and end up finding yourself with six useless arrows and some cash missing from your pocket. No one wants to be in that situation. That's why we are writing this outline based on the AMO (Archery Manufacturers Organization) standards.
There are a few types of measurements you might encounter:
AMO Length: The length between the nock groove and the end of the shaft. This is a very common measurement and the way you want to go to ensure your arrows are of similar lengths, as it takes the nock groove into account.
Carbon-to-Carbon/Shaft Length: The length between each end of the shaft (also called carbon-to-carbon length). This is the simplest measurement of the three, and also the way that we here at Lancaster Archery Supply measures our custom cut-to-order arrows and shafts.
Physical Length: The length between the tip of the arrow and the end of the nock ears. This generally is not applied when arrow building and cutting, but we cover it because you might just encounter it and we want to help all newcomers cover the basics.
AMO Length:
AMO arrow length is defined by the Archery Manufacturers Organization as, "the distance from the bottom of the nock slot to the back of the arrow head." In layman's terms, this is the length between the point at which the arrow is nocked on the string and the end of the shaft. This does not include any insert, outsert, or tip.
The AMO length is vital because the length of nocks vary among manufacturers and models. So, keeping the measurement between the nocking point and the end of the shaft consistent will ensure that your built arrows maintain the same AMO length, regardless of nock variance.
Shaft Length:
Shaft Length is a rather straightforward way to measure an arrow, as it has no external factors outside of what the name describes. Often referred to as "carbon-to-carbon," shaft length is just the overall length of your arrow/shaft from one end of the carbon/aluminum to the other. This does not include any insert, outsert, tip, nock, or bushing.
This is the method that we here at Lancaster Archery Supply use when our customers order custom cut-to-length arrows, as it is the simplest measuring method. You do want to be careful to know both your shaft length and your AMO length, for they serve different and equally important purposes depending on your situation.
Physical Length:
Physical length is not used when building or measuring arrows. This is the overall length of your built arrow from the tip of the point to the end of the nock ears. When measuring arrows for custom building, be sure to avoid measuring from the rear of the nock to the tip of the point. Use Shaft Length or AMO Length.
Like I said at the beginning, it's not that simple.
Fortunately for us, though, it's not that complicated, either.