Frontier Personal Item Bags After Spirit Shut Down: What Fits Free in 2026

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The verdict

1. Spirit Airlines closed on 2 May 2026, so the comparison that used to matter is now a single question: what fits Frontier's free personal item? The answer is a bag no larger than 18 x 14 x 8 inches including handles, wheels and straps, and Frontier will let it weigh up to 35 lb — so buy on the exterior measurement, not the marketing size, and see personal item bags on eBay with those numbers written down.
2. The bag you bought for Spirit still works. Spirit's free personal item used the same 18 x 14 x 8 box that Frontier and American publish today, so nothing in your closet became obsolete when the airline did.
3. If you need more than the free allowance, Frontier's paid carry-on is unusually generous at 24 x 16 x 10 in and 35 lb — larger than the 22 x 14 x 9 in box at United, Delta, American, Alaska and JetBlue. Buy a bag to the 22 x 14 x 9 standard anyway and it will clear Frontier with room to spare.

Spirit Airlines Closed on 2 May 2026

Spirit Airlines ceased flying on 2 May 2026. In its own statement the carrier said "it is with great disappointment that on May 2, 2026, Spirit Airlines started an orderly wind-down of our operations, effective immediately," adding that all flights had been cancelled and customer service was no longer available. The airline had filed for bankruptcy twice since 2024 and a last-ditch federal support package did not come together.

For packing purposes that means three things:

• Spirit's published allowances no longer apply to any flight. There is no Spirit itinerary to size a bag for.
• spirit.com no longer resolves, so the airline's own baggage page can no longer be cited or checked by anyone. Any site still presenting "Spirit's current personal item rules" is quoting a dead page.
• The demand did not disappear with the airline. Frontier is now the mainstream ultra-low-cost option on most of those routes, and its allowances are the ones to learn.

If you are re-planning a route Spirit used to fly, the per-airline carry-on size table has the current limits for every carrier we could verify.

Frontier's Two Boxes in 2026

Frontier publishes both allowances on one page, and both are measured the honest way — with everything attached.

Frontier's wording is worth reading twice: the personal item "must be equal to or less than 18in by 14in by 8in, including handles, wheels, and straps" and "may weigh up to 35 pounds." A 35 lb allowance on a free personal item is extraordinary — it is more weight than Lufthansa's 8 kg allowance for a full cabin bag. In practice the size is the binding constraint, not the scale.

The second thing to notice is that Frontier checks the personal item at boarding: the airline states that "the size of your personal item will be checked during boarding" and that oversized items are "subject to an additional charge." The free allowance is measured, not assumed.

Frontier does not publish a fixed carry-on price — it says bag prices "vary depending on your travel dates and when you purchase them," and that a carry-on bought at the gate costs more than one added at booking. That is the single most expensive mistake on this airline, and it is entirely avoidable. Our companion piece on Frontier's personal item, measured works through what actually fits inside the 18 x 14 x 8 box.

The Old Spirit 18 x 14 x 8 Box

People still search for this, so here it is in one paragraph.

Spirit's free allowance was a personal item of 18 x 14 x 8 inches, and that is the same box Frontier publishes today and the same box American publishes for its personal item. The practical consequence is reassuring: a bag bought to Spirit's spec is still a compliant personal item on Frontier and on American, and it is comfortably inside the carry-on limit at every carrier in our table.

One caveat on sourcing, because it matters. Spirit's own website is gone, so we cannot re-read the original page — the figure above is stated here because two live carriers publish exactly those dimensions today, not because we could verify Spirit's historical page in September 2026. If you see a site quoting Spirit's fees or bundles as current, treat the whole page as stale.

Where the 18 x 14 x 8 Box Still Lives

This is the table that decides which bag to buy, and it is less uniform than most travelers expect.

United is the tightest measured allowance in US aviation at 17 x 10 x 9 in — 10 inches of width where Frontier gives you 14. If you fly both airlines, the United number is the one to build around; we take it apart in what actually fits United's personal item. JetBlue sits in between at 17 x 13 x 8 in. And three major carriers publish no number on the carry-on pages we read in September 2026, which means the under-seat space and the gate agent decide.

Buy for 17 x 10 x 9 in and you are compliant everywhere. Buy for 18 x 14 x 8 in and you are compliant on Frontier and American, and taking a risk on United.

Allegiant and Sun Country: What We Could Not Verify

Both carriers were on the list for this comparison and neither could be verified, so neither gets a row.

Allegiant's bag page is behind a bot-verification wall. Repeated requests, including from a real browser engine, returned Cloudflare's "performing security verification" page rather than the policy. We have no re-read figures for Allegiant and will not publish any.

Sun Country's bag pages returned an empty document. The baggage URL redirects to the homepage and the help-center page rendered no policy content to us at all.

We would rather leave two gaps than fill them with numbers we did not read on the airline's page. Check both carriers' own sites before you fly them, and note that both sell the carry-on as a paid extra on their cheapest fares — which is the pattern across ultra-low-cost carriers rather than an airline-specific quirk.

Three Bags That Clear Frontier's Boxes

Exterior dimensions, as published by the manufacturer, with wheels and handles included. Nothing here was measured by us.

LEVEL8 Luminous Textured Carry-On 18" — 20.2 x 13.7 x 9.2 in, 7.1 lb, 39 L, $159.99 as of September 2026. The smallest full spinner worth considering for Frontier's paid carry-on: it is nearly 4 inches inside the 24-inch limit and 2 inches inside the width, which is exactly the margin that keeps a bulging front pocket from becoming a gate fee. At 7.1 lb it leaves most of the 35 lb allowance for contents.

LEVEL8 Road Runner 20" — 21.7 x 14.5 x 9.6 in including handle and wheels, 9.5 lb, 38 L, $189.99 as of September 2026. A polycarbonate shell with a front laptop pocket and a published lifetime warranty that "covers functional aspects including shell, wheels, handles, and zippers." It clears Frontier's carry-on box easily and also fits the 22 x 14 x 9 standard on height and width, though its 9.6-inch depth is marginally over on a strict mainline sizer. Our full Road Runner breakdown has the detail — see LEVEL8 carry-ons.

Travelpro Platinum Elite carry-on — 23.5 x 14.5 x 9 in overall, 21 x 14 x 9 in case, 7.8 lb, 46 L, $390 as of September 2026. The most volume of the three inside Frontier's box, and the lightest per liter. Travelpro publishes both numbers and explains why: "When airlines publish carry-on size limits, they mean the overall size, wheels and handles included." At 23.5 in overall it is inside Frontier's 24-inch limit by half an inch — and over the 22-inch mainline standard, which is the trade-off. See the Platinum Elite spec review, then see Travelpro carry-ons or see current prices on eBay.

For the free allowance itself, a soft bag is the right instrument — it compresses under the seat where a shell does not. Our underseat personal item backpack review covers that side, and the carry-on size checker will test any dimensions you have against a specific airline.

The 18-Inch Trap in Personal Item Backpacks

Here is the problem with buying a "personal item backpack" without checking the spec sheet: most commuter backpacks are taller than 18 inches.

Two examples from a brand that publishes its dimensions clearly. The LEVEL8 Urban Backpack is 11.8 x 5.9 x 18.1 in (19 L, 2.56 lb, $159.99 as of September 2026) and the LEVEL8 Atlas Laptop Backpack is 12.6 x 6.5 x 18.6 in (31 L, 3.33 lb, $129.99 as of September 2026). Both are well inside Frontier's 14-inch width and 8-inch depth. Both are over the 18-inch height — by a tenth of an inch and by six tenths respectively.

A soft backpack compresses and a sizer is not a micrometer, so in practice these often pass. But "often passes" is not the same as compliant, and it is the wrong thing to rely on at a carrier that measures at the gate and charges when a bag fails. The lesson generalizes: check the published height first, because width and depth are rarely the problem — height is. Our explainer on listed versus overall dimensions covers the same trap on wheeled bags.

When It Is Cheaper Not to Take the Bag

Frontier's carry-on and checked prices move with the date and with how early you buy, and a bag added at the gate costs the most. Three ways out, in order of how often they work:

Pack to the free box. If the trip is three or four days, the 18 x 14 x 8 personal item at 35 lb is a real allowance rather than a token one. This is the option most Spirit refugees underuse.

Buy the bag allowance at booking, never at the airport. Frontier states plainly that prices are lowest when purchased in advance.

Send the luggage separately. For a family, a ski trip or anything where the bag fees multiply, door-to-door shipping stops being exotic — you can ship the bag instead with Luggage Forward and travel with a personal item. Run the numbers against your actual fare; on a single short trip the free box usually wins, and our roundup of budget weekend carry-ons covers the cheap end if you would rather solve it once with a bag.

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FAQ

What is Frontier's personal item size?

Frontier publishes a free personal item of 18 by 14 by 8 inches, including handles, wheels and straps, weighing up to 35 pounds. The airline checks the size during boarding and charges for items larger than the allowed dimensions. That allowance comes with every ticket.

Is the Spirit personal item size still valid?

Spirit Airlines ceased operations on 2 May 2026, so its allowances no longer apply to any flight and its website no longer resolves. The 18 by 14 by 8 inch box Spirit used is still published by Frontier and by American, so a bag bought to Spirit's old spec remains a compliant personal item on both.

What is the difference between Frontier's personal item and carry-on?

The personal item is 18 by 14 by 8 inches and free with every ticket. The carry-on bag is 24 by 16 by 10 inches, weighs up to 35 pounds, and is either bundled with your fare or bought separately, with the highest price paid at the gate. Both dimensions include handles, wheels and straps.

Does a travel backpack count as a personal item on Frontier?

It depends on the shape, not the liters. Frontier measures 18 by 14 by 8 inches including handles, wheels and straps, and volume is not a compliance number. For scale: the LEVEL8 Atlas laptop backpack holds 31 liters and is already 18.6 inches tall, which is over Frontier's height limit, so a larger travel pack is very likely to be over too. Check the published exterior height before you buy.

Which airline has the biggest free personal item allowance?

Among the US carriers we could verify in September 2026, Frontier and American publish the largest measured personal item at 18 by 14 by 8 inches, and Frontier adds a 35 pound weight allowance. United publishes the smallest at 17 by 10 by 9 inches. Delta, Southwest and Alaska publish no numeric limit on their carry-on pages and simply require the bag to fit under the seat.