The 2018/19 rates will be:
- Income up to £11,850 - 0% income tax. This is your personal tax-free allowance.
- Income between £11,850 and £46,350 - 20% income tax
- Income between £46,351 and £150,000 - 40% income tax
- Income above £150,001 - 45% income tax
The personal allowance will reduce by £1 for every £2 you earn over £100,000. So, by the time you earn, £123,700, you'll pay income tax on everything you earn and get no personal tax-free allowance.
http://www.telegraph.co.uk/money/consumer-affairs/budget-much-income-tax-will-pay-personal-allowance-goes/