The 40 tax threshold is not a commonly used term in tax law. However, the income tax threshold is the income level at which a person begins paying income taxes. It is also known as the personal allowance in the UK, which is £12,500 for 2019/20. The tax bracket is a range of taxable income that is subject to a specific tax percentage. The brackets used to calculate your income tax depend on your filing status and taxable income. For example, for the 2023 tax year, the 22% tax bracket range for single filers is $44,726 to $95,375, while the same rate applies to head-of-household filers with taxable income from $59,851 to $95,350. Therefore, the 40 tax threshold is not a specific term used in tax law, and it is unclear what it refers to.