Reduced personal allowance

My personal allowance is reduced by a number larger than expected. Could you confirm what types of income and expenses are taken into account for the calculation? Is dividend income included, even if below the tax allowance of £2000? And are expenses taken into account? Thanks.

Hi,
Your total taxable income is what is taken into account so this can be earnings, company benefits interest and dividends.
If your income is over £100,000 your personal allowances are then reduced:
Income Tax rates and Personal Allowances