Question: what is the difference between 3/4 and full size guitar?
Answer: Even if the total length is far longer or shorter than 38 inches, if the scale length is around 25 inches or higher, it's a full-sized guitar. If the scale length is far below this range (eg: 20 inches or 50 cm), it is likely to be a scaled-down guitar such as a 3/4 guitar.