Take a look at this picture and you will see the size difference for each guitar. From Left to right, the guitars are Concert Ukulele, 1/2 size guitar, 3/4 size guitar, full size guitar. Apologies that the full size acoustic is on a stand, but it has a curved back so it doesn’t stand up on it’s own. I hope you will find this useful. The ukulele is a concert size – you can also get a smaller ‘soprano’ size, but they aren’t much different. Anyone could play either size really. If buying for someone very young, then a soprano would be the better choice. If buying for an adult, a soprano would be fine too really – they are both playable. The main playing difference here is the size of the frets, and the length of the fretboard. There is also a little difference in the sound due to the size difference.
I believe that if in doubt, buy a 3/4 size guitar – but read on for more info.
Most adults play a full size guitar, but just look at the type of guitar size that Ed Sheeran uses – his is only a 3/4 sized guitar, and he does pretty well playing it!
Generally, I would say that year 1-2, or possibly year 3, would be best to have a 1/2 size, and anyone from year 3 or 4+ would be fine with a 3/4 size. Anyone in high school would be fine with a 3/4 or a full size – but if they are quite small, 3/4 might be a better choice. Having said this, I have taught quite a few girls and boys in year 5 and 6 who have a full sized guitar and manage just fine. There are no rules really – you should head down to your local music shop and try out some different sizes, and if you are buying for someone else, ideally take them with you and get them to try out different sizes. If you are buying a guitar as a gift then hopefully my advise has been helpful to you. Remember; if in doubt, go smaller.
The main differences between a 1/2 size and a 3/4 size is that the body is smaller, the neck is a bit smaller, and the strings are a bit closer together – this makes the 1/2 size perfect for kids with small hands and small fingers, because they will find it easier to play. They will however grow out of this size, and find it difficult to play when their fingers get bigger or longer.
The main difference between the 3/4 and the full size is the width of the body, and also the depth, meaning that they can be tough to hold comfortably for smaller people. There are different types of full size acoustics too – I quite like the rounded back on mine, because some of the bigger guitars are quite chunky and uncomfortable – particularly if you are using it all day to teach with like me. There can be a trade off with sound though – usually the bigger the guitar, the richer and more rounded the tone is.
The ukulele on the left is a concert size, and the ones on the right are both Soprano.