Allegiant Personal Item Size 2026: Free Bag Rules & Fees

Allegiant's personal item size in 2026 is 18 × 14 × 8 in (45 × 35 × 20 cm), and every passenger may bring one on board for no charge. It must be stored completely underneath the seat in front of you — personal items may not go in the overhead bin, which belongs to the people who paid for it.

There is no weight limit. Allegiant publishes dimensions only, so a densely packed under-seat bag flies exactly as free as an empty one. And because Allegiant sells a single fare type with bags as à-la-carte add-ons, no ticket tier can take the personal item away — it comes with every fare, full stop.

Everything else — carry-on, checked bags, seat selection, even printing your boarding pass at the airport — costs money. This page covers all of it, verified against Allegiant's official baggage page in July 2026, so your total bag spend can stay at $0.

Yes — by size, not by name. Allegiant's official examples read like a 2009 office (purse, briefcase, laptop computer, camera case, portable electronics of similar size) and never say the word backpack — but the rule is the tape measure, not the label. A backpack within 18 × 14 × 8 in (45 × 35 × 20 cm) that stows under the seat boards free, and the airline's own 2023 size announcement grouped book bags right alongside the briefcases.

The catch is the count, not the category: one personal item per passenger. A backpack AND a purse is two items, and one of them gets charged. The merciful footnote: a jacket, an umbrella, food for the flight, one item of reading material and a diaper bag don't count against the allowance — so the sandwich flies free even when a second tote wouldn't.

One last line of fine print worth memorizing: the published dimensions include wheels, pockets, handles and decorations. Allegiant will measure your bag's pom-pom. Budget your 18 inches accordingly.

Yes — and it has done so longer than anyone else still flying. Allegiant became the second airline in America to charge for the overhead bin in April 2012, adopting Spirit's 2010 invention at up to $35 per segment. Spirit permanently ceased operations on 2 May 2026, which leaves Allegiant as the elder statesman of the American carry-on fee: fourteen years and counting.

The 2026 carry-on — 22 × 16 × 10 in (55 × 40 × 25 cm), no published weight limit — is sold per bag, per segment, non-refundable, at an official range of $10–$75. The ladder, verified July 2026: from ~$10 at initial booking (the route decides), $15–$70 later via Manage Travel or online check-in, and a flat $75 at the airport — counter and gate alike. A connection or round trip doubles all of it.

The personal item is the one bag on the menu that never touches this ladder: it costs what it has always cost — nothing.

Yes, and it's the change that still confuses everyone: on 1 March 2023 Allegiant enlarged the personal item from 16 × 15 × 7 in to 18 × 14 × 8 in — about 20% more volume — while the carry-on grew 25% to 22 × 16 × 10 in and the checked-bag weight limit rose from 40 to 50 lb.

Three years later, the internet hasn't caught up. Big-name guides carrying 2026 datelines still print the dead 16 × 15 × 7 figure, and marketplaces still sell "Allegiant personal item" duffels cut to the old spec — inches of free allowance left on the table. If a page or a product quotes 16 × 15 × 7, you're reading an archive.

Since then: nothing. Independent 2026 roundups confirm no further dimension changes through mid-2026 — the sizes held while the fees crept. Both facts are logged, with dates, further down this page.

Assume strict. 2026 guides describe an airline known for enforcing its baggage rules to the letter, sizers stand at the boarding gates, and the official policy reserves the right to verify every carry-on and personal item prior to boarding. The test is binary: a bag either drops fully into the frame or it doesn't, and one inch of bulge on one side bills the same as a suitcase.

Traveler reports do say enforcement varies by airport and by agent — one boarding waves everyone through, the next sizes every second bag. That variance is not a loophole; it's a lottery where the losing ticket costs $75, and you buy a fresh ticket every segment.

For the record: unlike Frontier, which confirmed paying gate agents a bonus for flagging oversize bags, there is no public evidence Allegiant does the same. It doesn't matter. A bag that measures inside 18 × 14 × 8 in when packed passes on every shift — then the sizer is just furniture.

Allegiant's policy is precise: a personal item that doesn't fit completely under the seat may be considered a carry-on bag, and passengers will be charged accordingly. At the gate, "accordingly" means the $75 rate — per bag, per segment, non-refundable.

Run the arithmetic once and it stays with you: the same overhead bag costs from ~$10 added at booking and $75 caught at the gate — $150 on a round trip, frequently more than the famously cheap fare itself. Allegiant doesn't hide any of this; the ladder is published. The gate is simply the most expensive shelf in the store.

The fix is not hoping for a generous agent — it's a bag that cannot be reclassified because it measures inside the published number when packed. Arithmetic beats luck at every gate, on every shift, in both directions of the round trip.

No. Allegiant publishes no weight limit for the personal item — confirmed across the 2026 guides — and the boarding process involves sizers, not scales. 18 × 14 × 8 in of bricks flies free; 18 × 14 × 9 in of feathers costs $75. On Allegiant, dimensions are law and physics is not.

So measure the only thing that gets measured. Pack as if you leave tomorrow, stand the bag up, and tape every side at its fattest point — wheels, pockets, handles and decorations included, because the policy includes them too. Soft bags clear the tape empty, then thicken past the 8 in line on the day they're actually full.

Our backpack's fit check, in Allegiant's units: 15.7 × 11.8 × 7.9 in (40 × 30 × 20 cm) — more than 2 in of spare room in both length and width, and a hardshell depth that sits under the 8 in line. Packed size equals published size, because the shell can't bulge.

Every figure above traces back to a date below — one canonical line per change, so nothing on this page floats free of a source.

April 2012 — Allegiant becomes the second US airline to charge for a carry-on, at up to $35 per segment, two years after Spirit invented the fee. 2 September 2014 — the $5 fee to print a boarding pass at the airport takes effect; against that backdrop, a free under-seat bag starts to read like a love letter.

1 March 2023 — the big enlargement: personal item 16 × 15 × 7 → 18 × 14 × 8 in (+20%), carry-on 22 × 14 × 9 → 22 × 16 × 10 in (+25%), checked weight 40 → 50 lb. 2023–2026 — the sizes hold while the fees creep: the official carry-on window widens to $10–$75, with a flat $75 anywhere at the airport.

2 May 2026 — Spirit permanently ceases operations, leaving Allegiant as the longest-running carry-on-fee airline still flying in America. July 2026 — this page re-checked line by line against Allegiant's official baggage and optional-services-fees pages.