Hello,

For the 2018/19 tax year, you can earn up to £11,850 per year before they start paying income tax. So if you've got a part-time job and earn under £11,850, you won't pay a penny.

Above your Personal Allowance, the amount you pay depends on the amount you earn. In 2018/19: the first £11,850 is tax-free; you pay 20% tax on earnings between £11,851 and £46,350. Few students are likely to be earning over £46,350, but if you do, you pay 40% on this.

hope this helps you !