A change in marital status affects tax filing

A change in a couple’s marital status, such as a separation or divorce, affects their tax situation. The IRS considers a couple married, for tax filing purposes, until they get a final decree of divorce or separate maintenance.

Update tax withholding
When a taxpayer divorces or separates, a new Form W-4, Employee's Withholding Certificate should be provided to their employer. If they receive alimony, they may have to make estimated tax payments. Taxpayers can figure out if they're withholding the correct amount with the Tax Withholding Estimator on IRS.gov.

Tax treatment of alimony and separate maintenance 

Amounts paid to a spouse or a former spouse under a divorce decree, a separate maintenance decree or a written separation agreement may be alimony or separate maintenance for federal tax purposes

• Certain alimony or separate maintenance payments are deductible by the payer spouse, and the recipient spouse must include it in income

However, not all payments are considered alimony or separate maintenance. It doesn't include:
• Child support
• Noncash property settlements – whether in a lump-sum or installments
• Payments that are your spouse's part of community property income
• Payments to keep up the payer's property
• Use of the payer's property
• Voluntary payments

Rules related to dependent children and support
Generally, the parent with custody of a child can claim them on their tax return. If parents split custody fifty-fifty and aren't filing a joint return, they'll have to decide who claims the child. If the parents can't agree, they should refer to the tie-breaker rules in Publication 504, Divorced or Separated Individuals.

Child support payments are never deductible by the payer and aren’t taxable to the payee. Additionally, if a divorce or separation instrument provides for alimony and child support and the payer spouse pays less than the total required, the payments apply to child support first. Only the remaining amount is considered alimony.

Report property transfers, if needed
Usually, if a taxpayer transfers property to their spouse or former spouse due to a divorce, there's no recognized gain or loss on the transfer. People may have to report the transaction on a gift tax return.