Ryanair Carry-On Rules — What Actually Fits (and What You'll Pay For)
Will a 40L Backpack Fit on Ryanair?
A 40L backpack exceeds Ryanair’s strict 55 × 40 × 20 cm (21.7 × 15.7 × 7.9 in) carry-on dimensions on both height and depth — this bag will likely need to be checked.
Without priority boarding, only a small personal item (40 × 20 × 30 cm (15.7 × 7.9 × 11.8 in)) is included free. A 40L bag exceeds that limit. Bags that fail the sizer box face gate-check fees — Ryanair's enforcement is among the strictest in Europe.
Placement: Likely Does Not Fit
Confidence: Low
Best For: 3–7 Day Trips
Last updated: March 2026
Ryanair's cabin-bag limit of 55 × 40 × 20 cm (21.7 × 15.7 × 7.9 in) is strictly enforced with a sizer box at the gate. The 20 cm (7.9 in) depth limit is the critical constraint — slim carry-on-specific travel packs can clear it, but standard hiking-shape 40L bags typically do not. A 40L bag exceeds Ryanair's free personal item envelope by a wide margin (40 × 20 × 30 cm (15.7 × 7.9 × 11.8 in)). To bring it on board, you must purchase priority boarding. Bags that fail the sizer box are gate-checked with risk of gate-check fees. Pre-purchasing priority online is significantly cheaper than paying at the gate. Carry-on allowances vary by ticket type — stricter size limits are commonly enforced.
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Gear
Bags That Work on Ryanair at 40L
Based on Ryanair’s 21.7 × 15.7 × 7.9 in carry-on limit and real bag dimensions.
Borderline — Compressible
Coowoz Travel Backpack 45L
Budget 45L at 18.5 × 12.6 × 8.7 in. The most compact option for this capacity range. Soft-sided and compressible — the 8.7" depth is closest to Ryanair's 7.9" limit.
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Rolling alternative — Borderline
Travelpro Maxlite 5 International Spinner
39L rolling carry-on at 21.75 × 15.75 × 7.75 in. The only roller close to Ryanair's depth limit — clears the 7.9" depth, but exceeds height and width by ~1 mm each. Rigid frame means no compression margin. May pass a lenient sizer check, but not guaranteed on strict enforcement days.
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Packing optimization
Compression Packing Cubes
On strict airlines like Ryanair, packed depth is what causes sizer failures — not bag size alone. Compression cubes reduce clothing volume by 20–30%, and soft bags compress better than rigid ones. If you're close to the limit, organized compression is the difference between boarding and gate-checking.
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Stay Carry-On Only
This setup exceeds typical carry-on capacity. Add a personal item or check a bag.
Gear
Recommended Bags for This Trip
These recommendations are based on real bag dimensions compared to Ryanair carry-on limits, plus how well each bag fits a 40-liter packing load.
Packing Reality Check
When Does a 40L Bag Work Well on Ryanair?
Best Case
- 5–7 day trips
- Standard packing style
- Mild climate
- Priority boarding purchased
- Efficient packers
- Laundry available
Becomes a Tight Fit
- Any scenario where the bag holds more than 30L of packed items
- Ryanair's sizer box — 20 cm (7.9 in) depth makes most 40L bags non-compliant
- Gate fee of €30–50 wipes out any savings vs booking checked luggage
- Rigid or semi-rigid bags with no compression capability
Ryanair Bag Policy
Ryanair Carry-On Policy at 40L
| Personal item (free) |
40 × 20 × 30 cm (15.7 × 7.9 × 11.8 in) — must fit under the seat |
| Carry-on (priority only) |
55 × 40 × 20 cm (21.7 × 15.7 × 7.9 in) — requires paid priority boarding |
| Weight limit |
10 kg for carry-on; no stated weight limit for personal item |
| Enforcement |
Strict — bags are measured at the gate; oversized items may be charged |
| Fit at 40L |
Most 40L bags exceed the 20 cm (7.9 in) depth limit. Only slim, carry-on-specific designs have a realistic chance of passing the sizer box |
For a full breakdown of size limits, boarding rules, and exceptions, see our airline carry-on rules guide →
Bottom Line
- Ryanair's 55 × 40 × 20 cm (21.7 × 15.7 × 7.9 in) limit is strictly enforced with a sizer box — the 20 cm (7.9 in) depth limit is the deciding dimension
- Most standard 40L bags exceed the depth limit — only slim carry-on-specific designs clear the sizer
- Without priority boarding, only a small personal item (40 × 20 × 30 cm (15.7 × 7.9 × 11.8 in)) flies free — a 40L bag exceeds that
- Risk of gate-check fees is high if the bag fails the sizer box — pre-purchase priority online
Airline enforcement
How Strict Is Ryanair With Carry-On Bags?
Ryanair is one of the strictest airlines in the world for carry-on enforcement. Every passenger must place their bag in a physical sizer box at the gate — if it doesn't fit, you pay a fee and it goes in the hold. The free allowance is one small personal bag (40 × 20 × 25 cm (15.7 × 7.9 × 9.8 in)) that fits under the seat. Anything larger — including most backpacks over 20L — requires Priority Boarding (from ~€6–8), which allows a 55 × 40 × 20 cm (21.7 × 15.7 × 7.9 in) cabin bag in the overhead bin. The 20 cm (7.9 in) depth limit is the binding constraint. Most backpacks exceed 20 cm (7.9 in) when packed, even if height and width are within range. Ryanair charges €/£30–50 at the gate for non-compliant bags — more than the Priority Boarding upgrade costs. Weight is enforced: 10 kg for cabin bags. Gate agents use handheld scales. There is no soft enforcement here. Ryanair staff are trained to catch oversized bags and the airline profits from gate fees. If you're flying Ryanair, buy Priority Boarding and measure your bag before you leave home.
Size insight
40L Backpack on Ryanair: What Actually Changes?
A 40L backpack is a serious gamble on Ryanair. At full capacity, every 40L pack exceeds the 55 × 40 × 20 cm (21.7 × 15.7 × 7.9 in) cabin bag limit — particularly the 20 cm (7.9 in) depth. Even underpacked, most 40L bags are at the edge. The sizer box at the gate doesn't forgive a few millimeters. If your bag fails the sizer, Ryanair charges €30–50 at the gate to put it in the hold. Some travelers make it work by packing at 25–30L of actual gear in a 40L bag and relying on compression. But if you're actually filling a 40L bag for Ryanair, you should plan to check it or switch to a smaller pack.
Notes
How Accurate Is This?
Ryanair's free cabin item is 40×20×25 cm (under-seat); paid priority boarding adds a 55×40×20 cm (21.7 × 15.7 × 7.9 in) carry-on to the overhead bin. The dimensions translate roughly to 16×8×10 inches (free) and 22×16×8 inches (paid). Enforcement is extremely strict—sizers are deployed at every gate, and oversized bags incur €20–€50 fees on the spot.
A 30L or 40L backpack will not fit Ryanair's free allowance and requires purchase of priority boarding (typically €4–€15 upfront). Without priority, your larger bag must be checked, which carries additional fees. Ryanair's low fares come with tight packing expectations and strict dimensional compliance.
Unlike US carriers, Ryanair does not negotiate bag size at the gate. If your bag sizes exceed the sizer slot, you pay the fee or gate-check immediately. Weight limits are not enforced, but dimensions are absolute.
This is a planning tool to estimate capacity; actual gate acceptance depends on strict dimensional compliance and priority boarding purchase. For larger backpacks, factor priority boarding cost into your Ryanair fare calculation.
