Carry-On Size Calculator: Linear Inches, Dimensions, and How to Check

Measure your packed bag before using the bag fit checker. Airline policies can specify maximum sides, a sum of dimensions, or both. Those rules are different: a matching sum cannot cancel an oversized side.

Three calculations with different meanings

A 55 × 40 × 23 cm bag has a linear total of 118 cm, about 46.46 inches. Its rectangular exterior volume is 50,600 cubic centimetres, or 50.6 litres. That is not its usable packing capacity: shape, walls, wheels and handles affect the interior.

For comparison, 60 × 35 × 23 cm also sums to 118 cm, but its rectangular volume is 48.3 litres. Equal linear totals do not imply equal volume or the same fit.

Worked Air New Zealand example

Air New Zealand publishes 55 × 40 × 23 cm, including wheels and handles, and a 118 cm total. A 55 × 40 × 23 cm bag reaches both standard limits. A 60 × 35 × 23 cm bag reaches the same sum but exceeds the 55 cm maximum side. It does not pass the standard box rule.

Q300 aircraft limit depth to 22 cm. The checker does not select the aircraft, so check that exception separately. Economy also limits the main bag to 7 kg; premium cabins allow two bags sharing 14 kg, with neither above 10 kg. The checker tests one bag and does not total two bags together.

Open the Air New Zealand checker, enter the packed dimensions and weight, and select the applicable class. Read the airline guide for personal items and exceptions.

Measure and convert consistently

1. Measure the complete packed exterior, including protrusions and expanded pockets.
2. Keep all three measurements in the same unit before adding them.
3. For centimetres to inches, divide by exactly 2.54. For inches to centimetres, multiply by 2.54.
4. Compare every published side and any linear total. Keep unrounded measurements for a boundary decision.
5. Check weight, fare inclusion and the operating carrier separately.

For example, 45 linear inches is exactly 114.3 cm. It is not a universal US-airline rule. Use the policy for your selected carrier rather than transferring one airline’s sum to another.

A soft bag can change shape when packed, but the final packed size must still comply. Soft material does not grant extra centimetres, and a numerical result does not guarantee cabin storage space. Use the route tool to compare the carriers on a connecting itinerary.

Source: Air New Zealand baggage dimensions and allowances.