When Is Luggage Officially Declared Lost? The 21-Day Rule

Most major U.S. airlines declare a bag officially lost after 21 days without recovery. On international flights, the Montreal Convention sets the same 21-day threshold. The moment matters: full liability applies — up to $4,700 on domestic flights under 14 CFR Part 254 and approximately $2,025 (1,519 SDR) on international flights under the Montreal Convention, Article 17(3). ^{[1] [2]}

Why the declaration moment matters

Before a bag is declared lost, the airline treats it as delayed. That means interim expense reimbursement for essentials, a refunded checked-bag fee, and an active search. Once the bag is declared lost, three things change at once.

Full liability applies. The delayed-bag stage covered reasonable necessities. The lost-bag stage covers the value of the bag and its contents, up to $4,700 per passenger on domestic flights and approximately $2,025 (1,519 SDR) on international flights. ^{[1] [2]} Airlines pay depreciated value, not replacement cost. ^[3]

The claim-filing clock starts. Most U.S. airlines require a written compensation claim within 30 days of the flight date. ^{[4] [5] [6]} International itineraries follow the Montreal Convention, which requires written complaints within 21 days for delay and preserves the right to legal action for two years from arrival. ^[2]

Itemized inventory is required. Airlines will not pay a lost-bag claim on a verbal description. You need a written list of every item, estimated value, purchase date, and — ideally — receipts or photos. Depreciation applies. DOT Fly Rights ^[3]

Declaration windows by U.S. airline

Every major U.S. carrier converges on the same 21-day outer limit. American Airlines adds an internal escalation step at day 5, which is useful to know if you want your case reviewed sooner. Written-claim deadlines run from the flight date, not the declaration date — which is why filing early matters.

On international itineraries, the Montreal Convention supersedes the carrier’s domestic rule: a bag is deemed lost at 21 days, a written complaint for delay must be filed within 21 days, and legal action must be brought within two years of arrival. ^[2]

Delayed vs. declared lost: what the airline owes at each stage

The dollar math shifts sharply at the 21-day line. Here is what you can claim at each stage, and why the transition matters.

While the bag is delayed (days 0-20)

• Reasonable interim expenses — toiletries, a change of clothes, medication. The DOT requires “reasonable, verifiable, and actual incidental expenses”; there is no fixed federal daily cap. ^[3]
• Airline-specific per diems. Delta offers $50 per day for the first 5 days while the bag is delayed. ^[5] Other carriers use similar internal caps; these are airline policy, not federal regulation.
• Refunded checked-bag fee if the bag is not delivered within 12 hours on a domestic flight, 15 hours on a short-haul international flight, or 30 hours on a long-haul international flight. ^[3]
• Keep every receipt. “Verifiable” is a DOT requirement. Receipts are what separate a paid claim from a denied one.

After the bag is declared lost (day 21 onward)

• Full liability applies. Up to $4,700 per passenger on domestic flights. ^[1] Up to approximately $2,025 (1,519 SDR) per passenger on international flights. ^[2]
• Interim expenses still count. Money you spent during the delay period counts against the same per-passenger cap; it is not a separate bucket. ^[3]
• Depreciated value, not replacement cost. Airlines apply depreciation to every claimed item. A three-year-old laptop pays out at depreciated value, not what you paid for it. ^[3]
• Excluded items. Most carriers exclude electronics, jewelry, cash, medication, and other high-value or irreplaceable items from the liability cap. Delta, American, and United all publish exclusion lists in their contracts of carriage. ^{[4] [5] [6]}

The distinction is not cosmetic. 74% of mishandled bags are delayed and recovered; only a small share are classified as lost. ^[13] When your bag crosses into the lost category, the economics of your claim change — and so do the airline’s documentation requirements.

How to file a claim after declaration

Filing is straightforward if the documentation is ready. The sequence is the same for every major U.S. carrier.

1. Confirm the declaration in writing. Email the airline’s baggage service office and ask for written confirmation that the bag has been declared lost, with the date. This establishes the start of the claim period and the end of the interim-expense window.
2. Assemble the itemized inventory. List every item, estimated value, purchase date, and — where possible — receipts, photos, or credit-card records. Flag any excluded items separately (the carrier will reject them, but you want the exclusion on the record).
3. Include your interim-expense receipts. These count against the same liability cap, so submit them together in a single claim rather than piecemeal.
4. File within the deadline. 30 days from the flight date for most U.S. carriers; 45 days for United domestic; 21 days for most international routes under the Montreal Convention. ^{[2] [6]}
5. Use the PIR reference number on every submission. Without it, airlines can — and do — stall the claim.

For step-by-step filing instructions, see our how to file a baggage claim guide. For a ready-to-send letter, use the claim letter template.

Next steps

• If your bag is still within the 21-day search window, stay in the delayed-bag workflow: keep receipts, claim interim expenses, and check the delayed luggage guide for what to do while you wait.
• If 21 days have passed without recovery, move to the compensation workflow: request written confirmation, assemble the inventory, and file within the carrier’s deadline. Start with the airline compensation hub for your specific carrier’s rules.
• If the airline denies the claim or fails to respond, the DOT baggage rules page walks through the federal complaint process.