So if you ever get asked, its 13 and 3/4 inches.
Ok so why have I measured a piece of string. Simple, I wanted some brackets for the exhausts on my motorbike. The company I was buying from quoted two diameters (?) so I used the string to measure the circumference and then used some maths off the internet which included a pie to calculate the diameter I needed.
But its good to know how long a piece of string is !