Income Tax rates and Personal Allowances
3. Income over £100,000
Your Personal Allowance goes down by £1 for every £2 that your adjusted net income is above £100,000. This means your allowance is zero if your income is £123,000 or above.
You’ll also need to do a Self Assessment tax return.
If you don’t usually send a tax return, you need to register by 5 October following the tax year you had the income.
You’ll get a letter telling you what to do next after you’ve registered.