There are nearly 1,000 different tax forms used by the IRS to report tax obligations. It’s no wonder the IRS faces thousands of tax returns with errors each year. Here are some of the most common:

Wrong names and Social Security numbers. Taxpayers regularly make mistakes by entering incorrect information for their spouses and dependents. If you recently married or divorced but haven’t yet changed your name with the Social Security Administration, you’ll need to file under your old name.

Errors in age and birthdate. Much of the tax code is based on age. Without the correct birthdate, your eligibility for tax benefits could be cast in doubt.

Incorrect bank account numbers. If you’re expecting a refund and want to have it direct deposited into your account, double-check your routing and account numbers. The IRS may catch most errors, but many are often missed. Once your refund is deposited in the wrong bank account, it’s very difficult to get it fixed.

Overlooking online donations. Many people forget about emailed receipts at tax time. Catch missing deductions by searching your email inbox for keywords such as “gift” or “donation” before you file.

Missing forms. Taxpayers can miss dividend, interest and brokerage forms (Form 1099s) they get from their banks and investment accounts. These potential missing forms now also include Form 1095, proof of health insurance. If a form is missing, it may cost you extra tax, penalties and interest.

Not signing the return. Don’t forget to sign your return! The IRS won’t accept an unsigned return, and many people forget this last step. An unsigned tax return is the same thing as not filing in the eyes of the IRS. You not only face penalties and fines, but your tax return is open for audit indefinitely.