If you have ever stood at a gate holding a bag you thought was fine and had to check it anyway, you know why this matters. Carry-on size limits have not changed much over the years - the standard is still 22 × 14 × 9 inches for most US carriers - but enforcement has. In 2026, airlines are using automated bag sizers at dozens of airports, and what used to be a loose honor system is increasingly a hard stop at the gate.
This guide gives you every major US airline's carry-on and personal item limits in one place, plus the things the airline websites bury: which fare classes lose carry-on access, how much the fee is if you get caught, and where the real measurement traps are.
The Master Table: Carry-On Sizes by Airline (2026)
| Airline | Carry-On Limit | Weight Limit | Personal Item | Carry-On Free? |
|---|---|---|---|---|
| American | 22 × 14 × 9 in | None (domestic) | 18 × 14 × 8 in | Yes (all fares) |
| Delta | 22 × 14 × 9 in | None (domestic) | Must fit under seat | Yes (all fares) |
| United | 22 × 14 × 9 in | None (domestic) | 17 × 10 × 9 in | Yes (except domestic Basic Economy) |
| Southwest | 24 × 16 × 10 in | None | 16.25 × 13.5 × 8 in | Yes (all fares) |
| Alaska | 22 × 14 × 9 in | None (domestic) | Must fit under seat | Yes (except Basic Economy) |
| JetBlue | 22 × 14 × 9 in | None (domestic) | 17 × 13 × 8 in | Yes (except Blue Basic) |
| Hawaiian | 22 × 14 × 9 in | 25 lbs | Must fit overhead | Yes (all fares) |
| Frontier | 24 × 16 × 10 in | 35 lbs | 18 × 14 × 8 in | No - fees apply |
| Spirit | 22 × 18 × 10 in | None stated | 18 × 14 × 8 in | No - fees apply |
| Allegiant | 22 × 16 × 10 in | None stated | 18 × 14 × 8 in | Varies by fare |
Note: Dimensions are always measured including wheels and handles at full extension. Policies are as of September 2026 - verify on each airline's website before booking, as policies change seasonally and by route.
The Standard 22 × 14 × 9 Group
Most major US legacy carriers share the same carry-on limit: 22 × 14 × 9 inches including wheels and handles. That covers American, Delta, United, Alaska, JetBlue, and Hawaiian.
In practice, this means any carry-on labeled as a "standard" carry-on from a reputable brand will fit. A July Carry-On (21.65 × 15.16 × 8.46 in), a Monos Carry-On Pro (22 × 14 × 9 in), an Away Carry-On, or an ITHINK brand carry-on sized to the 45-linear-inch standard will all clear the overhead bin on these carriers.
The catches to know:
United: Basic Economy on domestic routes does not include a free carry-on - only a personal item. This changed in 2024 and United has enforced it consistently since. If you book Basic Economy on a domestic United flight, your only free bag is the one that fits under the seat.
JetBlue Blue Basic: Same rule. Blue Basic fares include a personal item only. Everything else in JetBlue's fare ladder (Blue, Blue Plus, Mint) includes a free carry-on.
Alaska Basic Economy: No free carry-on. All other Alaska fares include one.
Hawaiian: The only major US carrier with a domestic carry-on weight limit - 25 lbs. No other US domestic carrier enforces carry-on weight on domestic routes. Hawaiian's limit is consistent with international airline practice and reflects its role as a hub between the mainland and Pacific routes.
Southwest: The 24 × 16 × 10 Exception
Southwest is the most carry-on-friendly major US carrier. Its limit is larger than the standard - 24 × 16 × 10 inches - and it applies to all fare classes. Every Southwest ticket includes two free checked bags and one free carry-on plus one personal item.
In practice, this means standard 22 × 14 × 9 carry-ons have more room than they need on Southwest. The extra width (16 vs 14 inches) and depth (10 vs 9 inches) give Southwest's overhead bins more flexibility for standard-sized bags and irregularly-shaped items.
The Southwest personal item limit is 16.25 × 13.5 × 8 inches - slightly more specific than most carriers. Laptop bags and tote bags typically fit without issue.
Frontier and Spirit: Carry-On Fees Are Now Significant
Frontier and Spirit both operate on a base-fare model where carry-on bags cost extra. Frontier's standard overhead bin bag fee in 2026:
- $69 if added at booking
- $99 if added at the gate
Spirit charges $65–$100 depending on route, timing, and where in the booking flow you add it. The cheapest way to bring a carry-on on either carrier is to pay for it when you book - gate fees can nearly double the carry-on cost.
Frontier's carry-on limit is larger than the standard: 24 × 16 × 10 inches, same as Southwest. It also has a 35 lb weight limit - the only US budget carrier that enforces carry-on weight.
Spirit's limit is listed as 22 × 18 × 10 inches - notably wider than the 14-inch standard used by legacy carriers. In practice, Spirit's overhead bins are standard sized, so the wider dimension is less meaningful than it sounds.
On both carriers, the personal item is free and must fit under the seat: 18 × 14 × 8 inches. A slim laptop bag, backpack, or personal-item-sized bag (like the Peak Design Travel Backpack in its compressed configuration) will make it under the seat without a fee.
If you are flying Frontier or Spirit, the math is simple: a personal-item-only packing strategy saves you $65–$100 per direction versus bringing a carry-on. On a round trip, that is $130–$200 that goes toward hotels instead of bags. For a guide to what fits in a personal item, see our personal item size guide.
2026 Enforcement: What Has Changed
Until recently, oversized carry-on enforcement at most US airlines relied on agents doing visual checks at the gate. That is changing.
United Airlines deployed automated bag-sizer scanners at over 35 airports in late 2025, with plans to expand to 80+ locations by the end of 2026. The scanners measure bags as they pass through the gate area and flag oversized items before boarding begins. What used to be a negotiable conversation with a gate agent is now increasingly an automated measurement.
American and Delta have tightened manual enforcement at busy hubs. Reports of gate-checked carry-ons at peak travel times have increased significantly compared to 2023.
What this means practically: If your bag is right at the 22-inch limit including wheels, it is going to make it. If you are flying with a bag that is slightly over - 22.5 inches, 23 inches - the new automated systems create real risk. The measurement includes wheels and handles. A bag marketed as "22 inches" may measure 22.5 or 23 inches at the wheel base.
The safest strategy: verify the manufacturer's external dimensions including wheels and handles, not just the stated size on the product page.
How Airlines Measure Your Bag
Airlines measure carry-ons from the outside, including:
- Height: Bottom of wheels to top of handle at full extension (or to the top of the bag if shorter)
- Width: Widest point, including exterior pockets, zippers, and any side expansion
- Depth: Front to back at the thickest point
This is why a bag marketed as "21-inch" may measure 22 inches or more when the wheels and handle base are included. Always use the manufacturer's stated total external dimensions - not the product name - when comparing to airline limits.
For the most common bags currently available:
| Bag | Stated Size | Full External Dimensions | Fits 22×14×9? |
|---|---|---|---|
| Away Carry-On | 21.7" | 21.7 × 13.7 × 9 in | Yes |
| July Carry-On | 21.7" | 21.65 × 15.16 × 8.46 in | Yes (width 1 in over limit - fits most US carriers) |
| Monos Carry-On Pro | 22" | 22 × 14 × 9 in | Yes |
| Béis The Carry-On | 21.5" | 21.5 × 14 × 9 in | Yes |
| Samsonite Winfield 3 | 20" | 20 × 14.5 × 9.5 in | Yes |
See our July vs. Monos comparison and Béis vs. Monos comparison for detailed specs on those bags.
Personal Items: What Always Fits Free
Every major US airline includes a free personal item on every fare (including budget carriers). The personal item must fit under the seat in front of you.
Standard personal item limits:
- American: 18 × 14 × 8 in
- Delta: Must fit under seat (no published dimensions)
- United: 17 × 10 × 9 in
- JetBlue: 17 × 13 × 8 in
- Southwest: 16.25 × 13.5 × 8 in
- Frontier, Spirit, Allegiant: 18 × 14 × 8 in
In practice, a standard slim laptop backpack (20L or smaller), a large tote, or a structured personal-item bag will fit under most seats. The depth dimension (8–9 inches) is the binding constraint - under-seat space is shallower than most travelers expect.
If you are flying Spirit or Frontier and want to avoid the carry-on fee, a 40L backpack compressed to personal-item dimensions will often pass. Soft bags are easier to manipulate than hard-shell carry-ons when space is tight.
Airline-by-Airline Notes
American Airlines
22 × 14 × 9 in carry-on limit. No weight limit on domestic flights. Personal item: 18 × 14 × 8 in. All fares include one free carry-on and one personal item - American has not introduced carry-on restrictions on any fare class. Basic Economy on American still includes a free carry-on, which differentiates it from United and Delta Basic Economy.
Check the American Airlines page for current fee structures.
Delta
22 × 14 × 9 in. No weight limit on domestic flights. Delta does not publish a specific personal item size but states it must fit under the seat. All fares (including Basic Economy) include one free carry-on plus personal item. In 2025, Delta quietly extended this policy to Basic Economy after United and American introduced carry-on fee tiers - Delta's Basic Economy with free carry-on is now a competitive differentiator for domestic bookings.
Check the Delta page for current fee structures.
United Airlines
22 × 14 × 9 in carry-on limit. Personal item: 17 × 10 × 9 in. Basic Economy domestic fares do not include a free carry-on - personal item only. Basic Economy on international routes follows the same rule. MileagePlus Premier members retain carry-on access regardless of fare class. United has the most active automated bag-sizer deployment in the US system as of 2026.
Check the United Airlines page for current fee structures.
Southwest Airlines
24 × 16 × 10 in. No weight limit. Personal item: 16.25 × 13.5 × 8 in. All fares on Southwest include one free carry-on plus one free personal item plus two free checked bags. Southwest has the most generous bag policy of any major US carrier. If you are packing heavy and want to avoid fees, Southwest is the carrier to book.
Alaska Airlines
22 × 14 × 9 in. No weight limit on domestic routes. All fares except Basic Economy include a free carry-on. Basic Economy passengers receive a personal item only. Alaska MVP, MVP Gold, and MVP Gold 75K members retain carry-on access on all fare classes.
JetBlue
22 × 14 × 9 in. Personal item: 17 × 13 × 8 in. Blue Basic fares include a personal item only - no free carry-on. All other JetBlue fares (Blue, Blue Extra, Blue Plus, Mint, and Mosaic) include a free carry-on. JetBlue's personal item allowance at 17 × 13 inches is slightly wider than United's, which gives more room for laptop bags with side pockets.
Hawaiian Airlines
22 × 14 × 9 in. Weight limit: 25 lbs. Hawaiian is the only major US domestic carrier with an enforced carry-on weight limit on domestic routes. If you are flying Hawaiian inter-island or to/from the mainland, weigh your carry-on before you leave. A full 22-inch hard-shell carry-on can easily reach 20–22 lbs when packed - the July Carry-On itself weighs 7.5 lbs empty. All fares include a free carry-on plus personal item.
Frontier Airlines
24 × 16 × 10 in. Weight limit: 35 lbs. Carry-on is not free - fees are $69 at booking, $99 at the gate. Personal item (18 × 14 × 8 in) is always free. Frontier's oversized carry-on limit is actually larger than most legacy carriers - the 24 × 16 × 10 dimension means standard 22-inch bags have room to spare. But the fee applies regardless of bag size.
Spirit Airlines
22 × 18 × 10 in. Carry-on is not free - fees range from $65 to $100 depending on route and timing. Personal item (18 × 14 × 8 in) is always free. Spirit has the widest carry-on allowance of any US carrier at 18 inches, though its overhead bins are standard-sized. Pay for the carry-on when booking - gate prices are significantly higher.
Allegiant Air
22 × 16 × 10 in. Carry-on policies vary by fare type - check Allegiant's site for current pricing. Personal item: 18 × 14 × 8 in. Allegiant sells carry-on access similar to Spirit and Frontier. Always add carry-on access at booking to avoid higher gate fees.
FAQ
What is the standard carry-on size for US airlines?
The standard is 22 × 14 × 9 inches including wheels and handles. American, Delta, United, Alaska, JetBlue, and Hawaiian all use this limit. Southwest allows larger bags (24 × 16 × 10 in).
Do US airlines enforce carry-on weight limits?
On domestic routes, almost never - except Hawaiian (25 lbs). On international routes, many carriers enforce weight limits of 15–22 lbs. If your itinerary connects on a foreign carrier, check that carrier's specific limit.
Can I bring a carry-on on a Basic Economy fare?
It depends on the airline. American Basic Economy includes a free carry-on. Delta Basic Economy (domestic) includes a free carry-on. United Basic Economy (domestic) does not - personal item only. Alaska and JetBlue Basic Economy fares do not include a free carry-on.
What happens if my carry-on is too big at the gate?
Most carriers will gate-check your bag to your destination at no charge - but only if it is slightly oversized. Spirit and Frontier will charge their standard carry-on fee ($65–$99) if your bag does not qualify as a personal item and you have not paid for carry-on access.
Is a 24-inch carry-on too big for most US airlines?
Yes. A bag labeled "24-inch" refers to its height and will typically exceed the 22-inch height limit on most US carriers. Southwest allows 24 × 16 × 10 in, but that is the exception. For most carriers, stick to bags at or under 22 inches of total height including wheels.
Does the July Carry-On fit standard US airline limits?
Yes, on most carriers. The July Carry-On measures 21.65 × 15.16 × 8.46 in - the width at 15.16 inches is slightly over the standard 14-inch limit, but most US airlines measure total linear inches rather than individual dimensions. The July Carry-On clears those thresholds. The July Carry-On Light (21.26 × 14.17 × 9.65 in) is closer to the strict 22 × 14 × 9 standard.
Bottom Line
The standard is 22 × 14 × 9 inches. If your carry-on fits that, it fits American, Delta, United, Alaska, JetBlue, and Hawaiian. Southwest is more generous (24 × 16 × 10 in) and free for all fares. Frontier and Spirit charge for carry-ons and enforce it - budget $65–$100 per direction if you need the overhead bin.
The 2026 shift worth knowing: United's automated bag scanners are now at 35+ airports and expanding. Visual-only enforcement is fading. Measure your actual bag - wheels and handles included - before your next trip.
For help choosing a carry-on that fits the standard, see our best carry-on luggage guide.