Have a look at your tax code on your payslip ( if you can get online to see it 😡 ) Eg the code 1150 equates to 11500 earnings before paying tax . Divide that number by 13 to see how much pay without tax you can earn each month ( 20% tax on the remainder ). Don't for get you pay NI on everything you earn each week above £162.01 and allow for tesco contributions too.