According to official HMRC data, if you earn £43,000 a year, you'll take home £2,731 every month after tax, as a net salary.
Your gross hourly rate will be £20.68 if you are working 40 hours per week.
Your total tax liability for the whole year will be £6,100, which means that you'll pay £508 in tax every month.
Apart from tax, you'll also have to pay National Insurance. You'll pay £4,124 National Insurance in the 2019 - 2020 tax year (or £344 per month).
According to our calculations, you'll have a total taxable amount (the part of your salary that is getting taxed) of £30,500 (we extracted your personal allowance from your yearly wage).
Apart from tax, you'll also have to pay national insurance, which is truly just another form of tax. You won't pay NI on the full amount of your salary - you can earn up to £8,632 a year (or £166 a week) without paying NI. The total amount that qualifies for NI from your salary is £34,368 per year, or £2,864 / month.