Mail letters to the IRS and government agencies
By Justin Winter · Updated September 16, 2026
The short answer
Letters to the IRS, state tax boards, DMVs, and other agencies can be sent as USPS Certified Mail for $12.99 online — the mail class the IRS itself recognizes for timely-filing proof under the "mailbox rule."
The math
The math on one certified letter.
| Option | Cost | Your time |
|---|---|---|
| paperplane, Certified Mail | $12.99, all in | About two minutes |
| At the counter | USPS fees, plus printing, an envelope and the trip | About ten minutes at the counter, plus the drive and the line |
USPS charges the same fees whoever hands the letter over. The difference is the trip, the form and the slip you keep for a year.
Usually the right pick: Certified Mail · $12.99
The IRS runs on postmarks. Under the timely-mailing-as-timely-filing rule (IRC §7502), a document postmarked by the deadline counts as filed on time — and a Certified Mail receipt is the textbook way to prove the postmark date. Responding to a CP2000 notice, filing an amended return cover letter, disputing a penalty: Certified, every time.
The same logic covers most agencies: state tax boards, unemployment offices, the DMV, USCIS correspondence, county recorders. Government mailrooms lose things; your Certified tracking number is what turns "we never got it" into "it was delivered on the 14th at 10:02 am."
Address precision matters more with agencies than anywhere else — the IRS uses different PO boxes by state and by form. Copy the exact address from the notice you received (it is usually printed in the corner), and let the USPS address check confirm it before payment.
One honest caveat: for actual tax returns close to a deadline, weigh e-filing first — it is instant. Physical Certified Mail is for the correspondence e-file cannot carry: notice responses, penalty abatement requests, and anything an agent asked you to mail.
This page is general information about USPS mailing options, not legal advice. Notice rules vary by state and by document. Check your lease, contract or local rules, or ask an attorney, before relying on it for a deadline.
Questions before you send
Why not go to the post office myself?
You can, and if your time is free it costs less. USPS charges the same fees whoever hands the letter over; paperplane does not replace the post office, it replaces the trip. The mailing record comes from USPS, not from us. $12.99 covers the printing, the envelope, PS Form 3800, a USPS address check before you pay and a handoff the next business day. For a letter you already know how to send, the counter is a fine choice.
What if they refuse the letter?
USPS tracking records what happened to it, including refused or unclaimed. You still have the mailing record. Rules on what that means vary, so check with your court or an attorney if a deadline depends on it.
If something goes wrong, do I pay?
If we cannot mail the letter, the hold on your card is released and you are not charged. If a letter fails after your card is charged, you are refunded automatically and in full.
Does the IRS accept Certified Mail as proof of filing?
Yes — the Certified Mail postmark date is treated as the filing date under the timely-mailing rule. Keep your receipt with the tracking number; it shows the acceptance date.
Do I need the Return Receipt for the IRS?
Usually the $12.99 Certified option is enough — the postmark proves timeliness. Add the electronic Return Receipt ($14.99) if you also want proof of the delivery date, e.g. for an appeal window.
Which IRS address do I use?
The one printed on the notice you are responding to. IRS addresses vary by state and form type, so always copy from your specific notice rather than a generic list.