Originally Posted by Jambo I think over the age of 16 you're legiable to be taxed, because you get your National Insurance number then and i think that's when everything starts tax wise. However, i'm not 100% sure, so if anybody could give the correct answer then you'd be helping me too. - Cheers

The legal age you can start being taxed is 15 years old. If you turn a loss in your business and you are not officially incorperated you are completely liable for your losses. But if you are incorperated no matter what age you are you are required to file taxes in the US.