For many taxpayers, mailing a check to the IRS still feels like the simplest option. You write the check, include the voucher, drop it in the mail, and move on.
But there’s one small requirement that can quietly derail that process if it’s overlooked: your IRS Identity Protection PIN, often called an IP PIN.
This six-digit number helps the IRS verify your identity and ensure your tax return is processed without unnecessary delays. If you’ve already been issued an IP PIN, it’s not optional. Before mailing anything to the IRS, it’s important to confirm whether this applies to you.
What Is an IRS IP PIN?
An IP PIN is a six-digit security code assigned by the IRS to certain taxpayers. Its purpose is simple: prevent someone else from filing a tax return using your Social Security number or ITIN.
If the IRS has issued you an IP PIN, it must be included on your tax return. That requirement applies whether you file electronically or by paper, and whether you mail a payment or not.
When an IP PIN is missing or incorrect, the IRS may pause processing while it verifies your identity. That can mean delays, mail notices, and additional follow-up steps that could have been avoided.
Who Needs an IP PIN?
Not everyone has one, but many taxpayers do and don’t realize it.
Originally, IP PINs were issued only to confirmed identity theft victims. Today, the program is open to eligible taxpayers who choose to opt in for added protection.
You may already have an IP PIN if:
- You opted into the IP PIN program in a prior year.
- The IRS issued one due to concerns about identity theft.
- You receive an annual IP PIN notice from the IRS.
Some taxpayers receive their IP PIN automatically by mail each year. Others must retrieve it by logging into their IRS Online Account. If online verification isn’t possible, the IRS offers alternative options, including a paper application or in-person verification.
If you’re unsure whether this applies to you, it’s worth checking before you file or mail a payment.
Why This Matters for Mailed Payments
When you mail a check to the IRS, fixing an issue afterward is rarely quick. If your return is flagged because an IP PIN was required but missing, processing may stop until your identity is confirmed.
That can lead to:
- Delayed refunds,
- IRS notices requesting additional information, and
- Extra stress during tax season.
Having your IP PIN ready before mailing anything helps keep your return moving and reduces the risk of unnecessary back-and-forth with the IRS.
4 Quick Tips to Stay on Track
- If it’s misplaced, it can be retrieved through the IRS before filing.
- An IP PIN is six digits and changes each year.
- If you’ve been issued one, it must be included on your return.
- Store it securely with your annual tax records.