How to amend a tax return

While finding a mistake after filing a tax return might feel catastrophic, the reality is that this happens to millions of taxpayers each year, like the 3.8 million taxpayers who filed an amendment to fix an error or make a change on their 2015 tax return. The good news is that there is a simple way to resolve it: filing an amended tax return. Taxpayers generally have up to three years from the filing deadline to amend their tax return and even claim a refund.

However, taxpayers do not need to file an amendment for every mistake. For example, the IRS can usually fix simple math errors, such as transposing numbers on Form W-2 wages when completing the return. A tax amendment isn’t required if the taxpayer agrees with the IRS’s correction.

How to amend a tax return: step by step

If a taxpayer does need to amend a tax return, the taxpayer must file Form 1040X and include documents to back up the changes on the amendment. These could include forms, schedules, statements, receipts or worksheets.

Then, the taxpayer must mail the 1040X to the IRS, with payment if required. If the IRS owes the taxpayer a refund, it will send the refund in about 8 to 12 weeks.

Take a Second Look for costly mistakes

Taxpayers who don’t know if they’ve made a mistake but don’t want to miss the three-year deadline to claim a refund in case they have made a mistake should take advantage of H&R Block’s free Second Look.

Taxpayers who prepared their returns themselves or had others prepare them can get a free Second Look review of their three prior-year returns. An H&R Block tax professional will determine if there are any mistakes or if they were eligible for credits that could have increased their refund. If H&R Block doesn’t find anything, the taxpayer doesn’t need to amend. If there is a mistake or overlooked tax benefit, the H&R Block tax professional can prepare a tax amendment (1040X).

Taxpayers can see if a Second Look is right for them with a free online assessment and schedule an appointment online or by calling 1-800-HRBLOCK.