The question is unclear. Each year, when you complete your tax return, you'll report the number and type of your dependents. However, perhaps you're referring to the number of dependent you include on your withholding form, the W4.
- When you have life changes:
- Lifestyle - Marriage, divorce, birth or adoption of a child, home purchase, retirement, filing chapter 11 bankruptcy
- Wage income - You or your spouse start or stop working or start or stop a second job
- Taxable income not subject to withholding - Interest income, dividends, capital gains, self employment income, IRA (including certain Roth IRA) distributions
- Adjustments to income - IRA deduction, student loan interest deduction, alimony expense
- Itemized deductions or tax credits - Medical expenses, taxes, interest expense, gifts to charity, dependent care expenses, education credit, child tax credit, earned income credit
Change Your Withholding
To change your tax withholding, use the results from the Withholding Estimator to determine if you should: (https://www.irs.gov/individuals/tax-withholding-estimator)