IRS LT16 Notice: Please Call About Your Overdue Taxes or Returns
An LT16 is an Automated Collection System letter saying the IRS wants to hear from you about an unpaid balance, unfiled returns, or both — it asks for contact within 10 days and signals the account is in active collection, a short step from levy notices.
Deadline calculator
The LT16 clock runs from the date printed on the notice — not the day you opened it.
Estimate only, based on the standard 10-day LT16 window. Your notice controls — always use the specific date printed on it.
What a LT16 actually means
The LT16 sits in the middle of the ACS sequence: past the polite service-center reminders, before the final levy notices. It often flags two problems at once — a balance due and missing returns — because the IRS generally won't resolve one without the other. No payment arrangement gets approved while required returns are unfiled.
The 10-day contact request isn't a levy deadline, but it isn't decorative either: accounts that stay silent after ACS letters move to CP504 and then a final notice of intent to levy. The useful way to read an LT16 is as the IRS handing you the agenda for one phone call — file what's missing, address the balance — while every resolution option is still cheap and available.
How to recognize a real LT16
The IRS sends it when it's trying to collect unpaid tax and/or its records show missing returns. The sample notice's headline says the account "has been assigned for enforcement action." It goes to businesses as well as individuals: the IRS sample bills three years of Form 941 payroll tax.
- Small text above the headline reads "Your account has been assigned for enforcement action," and the large headline is "Please call us about your unpaid taxes."
- The left column says "It's important that we hear from you within 10 days." The "What you need to do" box asks you to pay within 10 days, or call and be ready to give your monthly income and expenses.
- The upper-right box has a Case reference number in addition to the notice date and taxpayer ID. Have it ready when you call.
- The "Your billing details" table on page 2 lists each tax period with its form number (for example 1040 or 941), the amount owed, added interest, added penalty, and a total.
- For joint accounts, the notice says a copy goes to each spouse and that you should pay the amount due only once.
What to do, step by step
- 1Pull the full picture first: your IRS online account or transcripts show every year with a balance and every missing return, so nothing surprises you mid-call.
- 2Prepare and file any unfiled returns — compliance is the gate to every payment option.
- 3Decide your resolution before calling: full pay, installment agreement, Currently Not Collectible, or an Offer in Compromise candidate.
- 4Call the number on the notice (or have a representative do it) and set the resolution in motion — silence is the only truly bad response.
- 5If the balance is large or several years are unfiled, get professional help now, while the account is still pre-levy.
Illustrative example
Example: an LT16 that combines a balance and two missing returns
Marcus (an illustrative taxpayer, not a real client) received an LT16 in March showing $6,420 owed for 2022. He had also never filed for 2023 or 2024 because he did gig work and assumed he owed too much to file. The notice asked him to call within 10 days.
Before calling, he spent a week getting his wage and income transcripts and preparing both missing returns, which showed modest balances. He also wrote down his monthly income and expenses, since the notice says the IRS will ask for them to set up a payment plan.
On the call he gave the case reference number, said the two returns were being mailed that day, and asked for a plan covering all three years. He knew that if the IRS later said it had no record of returns he'd sent more than 10 weeks earlier, its guidance is to send signed copies rather than prepare new ones. Getting a plan in place at the LT16 stage also kept him from reaching a Notice of Intent to Levy. The notice explains that if one of those goes unpaid for 10 days, the late-payment penalty rises to 1% per month.
Names and numbers are made up to show how this notice typically plays out.
Mistakes that make a LT16 worse
- Treating 10 days as the levy deadline. It's how long the IRS gives you to make contact. Using that window keeps the account from moving to the next stage.
- Calling without numbers. The notice tells you to be ready with your monthly income and expenses, and a call without them often ends without a plan.
- Calling about the balance and ignoring the missing returns, or the reverse. The LT16 can cover both, and the IRS treats them as one account to resolve.
- Sending a new, different version of a return you already filed. If more than 10 weeks have passed, the IRS asks for a signed copy of the original.
- Paying twice on a joint account because each spouse got a copy.
What happens if you ignore a LT16
The IRS says it may take steps to collect everything owed. That can mean seizing wages or other property and filing a Notice of Federal Tax Lien, and penalties and interest keep growing. The notice also says the late-payment penalty rises from 1/2% to 1% per month if a Notice of Intent to Levy goes unpaid for 10 days.
Often comes before a LT16
Common questions
What happens if I ignore an LT16?+
The account keeps moving through Automated Collection: a CP504 (intent to levy your state refund) and then a final notice of intent to levy with a 30-day appeal window. After that, wage garnishments and bank levies can be served without further warning. The LT16 stage is when resolving things is still entirely on your terms.
Why does the IRS want returns filed before it will discuss my balance?+
Filing compliance is a precondition for every collection alternative — installment agreements, hardship status, and Offers in Compromise all require that your required returns are in. The LT16 pairs the two issues because the IRS resolves them as one account, not as separate problems.
Should I call the IRS myself or get representation?+
For a single year and a balance you can realistically pay, calling yourself is fine — have the notice and your figures ready. For multiple unfiled years, payroll taxes, or a balance you can't pay, a representative who negotiates with ACS daily will usually get a better arrangement and keeps you from committing to a payment you can't sustain.
Checked against IRS primary sources — see how we source these guides. You can verify any notice directly at IRS.gov. The dates and instructions printed on your specific notice always control. Official IRS explanation: Understanding your LT16 notice (IRS.gov).
- IRS: Understanding your LT16 notice
- IRS sample notice LT16 (PDF)
- Taxpayer Advocate Service: Notice LT16
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