I found out the hard way that a bag which sails through security as a personal item on United can get you stopped at the gate on Ryanair — which is exactly the kind of surprise this carry-on size chart is built to prevent. Every figure below was pulled directly from each airline’s own policy page, not copied from another blog.
Last verified: September 14, 2026. Airlines change these numbers without much notice, so this page gets rechecked on a regular cadence — if you’re reading this months from now, double-check anything close to a hard limit directly with the airline before you fly.
Carry-On and Personal Item Size Limits by Airline
US Carriers
| Airline | Carry-On (in / cm) | Personal Item (in / cm) | Notes |
|---|---|---|---|
| American Airlines | 22 x 14 x 9 / 56 x 36 x 23 | 18 x 14 x 8 / 45 x 35 x 20 | Both explicitly published |
| Delta | 22 x 14 x 9 / 56 x 35 x 23 (45 linear in. total) | Not explicitly published — “similar size to a purse, briefcase, or laptop bag,” must fit under the seat | No personal-item weight or size limit stated anywhere on Delta’s own page |
| United | 22 x 14 x 9 / 56 x 35 x 23 | ~9 x 10 x 17 (widely reported across independent sources; United’s own policy page did not return readable content on this pass — see Methodology) | Corroborated, not pulled directly — flagged below |
| Alaska Airlines | 22 x 14 x 9 / 56 x 35 x 23 | Not explicitly published — same soft “fits under the seat” language as Delta | |
| JetBlue | 22 x 14 x 9 / 55.9 x 35.6 x 22.9 | 17 x 13 x 8 / 43.2 x 33 x 20.3 | No weight limit, but must be liftable into the bin unassisted |
| Southwest | 24 x 16 x 10 / 61 x 41 x 25 | No exact dimensions published — just “must fit under the seat,” with purse/briefcase/laptop-bag examples | No weight limit on carry-on |
| Spirit | 22 x 18 x 10 / 56 x 46 x 25 (paid add-on, not free) | 18 x 14 x 8 / 45 x 35 x 20 (free) | Carry-on is a purchased option on Spirit, not included |
| Frontier | 24 x 16 x 10 / 61 x 41 x 25 | 18 x 14 x 8 / 45 x 35 x 20 | Only major US carrier with a stated carry-on weight limit: 35 lbs |
| Allegiant | 22 x 16 x 10 / 55 x 40 x 25 | 18 x 14 x 8 / 45 x 35 x 20 | No weight limit stated |
International Carriers Most Likely to Catch a US Traveler Off Guard
| Airline | Free Small/Personal Bag (cm) | Paid or Fare-Included Larger Cabin Bag (cm) | Notes |
|---|---|---|---|
| Ryanair | 40 x 30 x 20 | 55 x 40 x 20 (10 kg), Priority fare or paid | Free bag is markedly smaller than any US personal item |
| easyJet | 45 x 36 x 20 | 56 x 45 x 25, included with certain fares or paid | Same pattern as Ryanair |
| British Airways | 40 x 30 x 15 (small bag) | 56 x 45 x 25 (hand baggage) | Both are free/standard — two-bag allowance, no upcharge |
What Actually Trips People Up
Two major US carriers don’t publish exact personal-item dimensions at all
Delta and Alaska both use soft language — “similar size to a purse, briefcase, or laptop bag that fits under the seat” — instead of a hard number. In practice, “compliant” is really up to the gate agent that day.
A “Southwest-sized” bag isn’t automatically compliant everywhere else
Southwest and Frontier both allow a taller box (24 x 16 x 10″) than the 22 x 14 x 9″ standard shared by American, Delta, United, Alaska, and JetBlue. Pack to the bigger box and your bag may get gate-checked the next time you fly American.
Spirit’s sizes don’t map onto the industry standard the way people assume
Spirit’s free “personal item” and paid “carry-on” sizes are their own thing, and Frontier is the only major US carrier that puts an explicit weight limit (35 lbs) on carry-ons at all — most others have none.
The personal-item gap that catches business travelers connecting internationally
A bag that’s fine as a personal item on every US carrier (17-18″ x 13-14″ x 8″) is oversized for Ryanair’s or easyJet’s free under-seat allowance (40 x 30 x 20 cm ≈ 15.7″ x 11.8″ x 7.9″). This is a real, recurring complaint from US travelers connecting onto European budget carriers.
British Airways gives two free cabin bags
A full hand-baggage-size bag plus a smaller bag, as standard in economy — genuinely different from the one-free-item norm most US travelers expect.
Methodology
Every figure in the tables above was pulled directly from the airline’s own current policy page. The one exception is United’s personal-item figure (9 x 10 x 17″): United’s baggage page returned a JavaScript shell with no readable policy text on this pass, both through a direct fetch and through a rendered browser session, so that number couldn’t be pulled from united.com directly this round. It’s corroborated instead by multiple independent sources — including product listings specifically sized and marketed to United’s stated allowance — that converge on the same figure. It’s flagged in the table above rather than presented as directly sourced, and it’s the first thing to re-check by hand on united.com the next time this page gets updated.
Which Bag Should You Actually Buy
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If you only want to own one bag and never think about this again, pack to the 22 x 14 x 9″ standard — it clears American, Delta, United, Alaska, and JetBlue outright, and it’s under Southwest and Frontier’s bigger box too, so it never gets you gate-checked for being oversized. It just won’t clear Ryanair or easyJet’s free personal-item allowance if you’re connecting onto one of those — for that leg, you’re either paying for their larger cabin bag or packing a second, smaller bag for that portion of the trip. For a closer look at bags that hit that 22 x 14 x 9″ mark without cutting corners on build quality, see our guide to the best carry-on luggage for business travelers.
Frequently Asked Questions
Does my personal item fit on Ryanair?
Only if it’s 40 x 30 x 20 cm (about 15.7 x 11.8 x 7.9″) or smaller. Every US airline’s personal-item allowance is bigger than that, so a bag that’s compliant at home is very likely oversized for Ryanair’s free allowance — check your bag’s actual dimensions before that leg of the trip, not just whether it worked domestically.
Southwest vs. Delta: whose carry-on is bigger?
Southwest’s is bigger. Southwest allows up to 24 x 16 x 10″, while Delta caps out at 22 x 14 x 9″ (45 linear inches total). A bag sized for Southwest can be too big for Delta’s bin.
Which airlines have no carry-on weight limit?
American, Delta, United, Alaska, JetBlue, Southwest, and Allegiant don’t publish a carry-on weight limit — size is what’s enforced, not weight. Frontier is the outlier among major US carriers, with a stated 35-lb carry-on limit.
The Bottom Line
The number that actually matters is 22 x 14 x 9″ — that’s the box that clears the most US carriers outright, and it’s the one worth building a packing habit around if you fly more than one airline. Just don’t assume it travels internationally: the moment you’re connecting onto a European budget carrier, the rules reset, and the safest move is checking the specific airline’s page before that leg rather than trusting what worked on the flight before it.