Do I measure luggage with or without wheels and handles?

Always include wheels and handles in your measurement. Airlines measure the full external dimensions of a bag — including any protruding wheels at the bottom and the extended handle housing at the top. The airline's size limit applies to the bag as it would be placed in the overhead bin or bag sizer frame.

What is length, width, and depth on a suitcase?

On a typical upright rolling suitcase: length (or height) is the tallest dimension measured from the bottom of the wheels to the top of the bag or handle housing; width is the widest dimension measured side to side; and depth (or thickness) is the thinnest dimension measured from front to back. These correspond to the three numbers in an airline's size limit, though the labeling varies between manufacturers.

What tools do I need to measure luggage?

A flexible tape measure is ideal for suitcases with rounded corners and curved sides. A rigid ruler or metal tape measure works well for flat-sided bags. A second person helps for large bags, but it's possible alone. A marker and sticky notes are handy for recording measurements directly on the bag.

My bag is 1 cm over the limit — will it be rejected?

It depends on the airline and the route. Full-service airlines rarely measure bags unless the overhead bins are clearly full. Strict LCCs like Ryanair and Wizz Air use rigid metal sizer frames — a bag that's 1 cm over on any dimension won't fit and will be checked at the gate fee. For strict airlines, treat the published limit as a hard ceiling with no tolerance.

How do I measure a backpack that has an irregular shape?

Measure a packed backpack, not an empty one. Pack it as you would travel with it, then measure the maximum dimensions at the widest point in each direction. Hold the tape measure straight and parallel to the ground (for width and depth) or vertical (for height). If the backpack has side pockets or hip belt holders, measure with those in their most extended position.

How to Measure Luggage: A Step-by-Step Guide

Airline carry-on size limits are published in centimetres (or inches), and they apply to the full external dimensions of your bag. Measuring luggage correctly before a trip takes less than five minutes and can save you a surprise gate fee that costs 10 to 20 times what you paid for the flight.

This guide covers every step: the tools you need, how to measure each dimension correctly, how to account for wheels and handles, and what to do if your bag is right on the limit.

What You'll Need

A flexible tape measure — the kind used in sewing or tailoring. This is essential for bags with rounded corners, curved sides, or irregular shapes.
A rigid ruler or metal tape measure — useful as a second tool for flat-sided hard-shell cases.
A pen or pencil and a small piece of tape or a sticky note to record measurements on the bag itself.
The airline's published size limit — look it up on the airline's official website before you measure. Size limits vary between carriers and fare types.

A flexible tape measure costs very little and is the single most useful tool for this task. A metal tape measure alone will struggle on curved sides and may give inaccurate readings.

Step 1: Understand What Dimensions You're Measuring

Airlines express carry-on size limits as three numbers, typically in the format length × width × depth (or height × width × depth). The labeling varies, but they always mean:

Length (or height): The tallest measurement from bottom to top, typically the longest dimension of a rolling suitcase.
Width: The side-to-side measurement, typically the second-largest dimension.
Depth (or thickness): The front-to-back measurement, typically the thinnest dimension. This is the one most likely to catch you out.

For a typical upright rolling suitcase sitting on its wheels, length is measured vertically, while width and depth are measured horizontally.

Step 2: Pack the Bag as You Would Travel

Measure your bag packed, not empty. A soft-sided bag (nylon or canvas) changes shape significantly when filled. An empty bag may appear to be well within limits but bulge past them once packed with clothes.

Pack the bag fully — including everything you plan to carry — and zip or fasten all compartments before measuring. If a zipper strains or a pocket bulges, that shape is what you'll be measuring.

Step 3: Measure the Length (Height)

For a rolling suitcase on its wheels:

Stand the bag upright on a flat floor.
Extend the retractable handle to its lowest stored position (collapsed fully).
Measure from the very bottom of the wheels to the highest point of the bag or handle housing. The handle housing — the plastic or metal casing around the retractable handle — adds 3–6 cm to a typical cabin bag.
Record the number.

For a backpack or soft bag:

Hang it from a hook or have someone hold it upright.
Measure from the lowest hanging point to the highest point. If there's a top handle, include it.
If the bag sits on a flat surface, measure it that way — but account for any feet or bottom protectors.

Step 4: Measure the Width

Lay the tape measure across the widest horizontal dimension — typically side to side on a suitcase.
Measure the maximum width at the widest point. If the bag tapers, find the widest spot.
For suitcases, check whether the lid or any exterior pockets extend wider than the main body on either side.

Step 5: Measure the Depth (Thickness)

The depth measurement is the most commonly underestimated. This is the front-to-back distance — how thick the bag is.

For a suitcase lying flat on a table, measure from the back panel to the front face of the bag including any exterior pockets or zipper pulls.
For a backpack, measure from the back panel (where it rests against your back) to the furthest protruding point at the front, including any front pockets.
Make sure the bag is fully zipped. A bulging zipper adds depth.

Step 6: Include All Protrusions

This is where many travelers undercount:

Wheels: The wheels on a rolling suitcase extend below the base. On most cases, the wheels add 2–4 cm to the length measurement. Always measure to the bottom of the wheels, not the bottom of the bag body.
Handle housing: The retractable handle mechanism adds height. Measure to the top of the housing, not the top of the fabric.
Spinner feet: Four-wheeled (spinner) cases have a small ridge or frame at the bottom. Include this.
Exterior pockets: Side pockets and front zipper compartments all add to width and depth when packed. If a pocket adds depth when full, that adds to your total depth measurement.
Padded hip belt or sternum strap buckles: On travel backpacks, these can add width when stowed loosely.

Step 7: Compare Against Your Airline's Limit

Look up the airline's official carry-on dimensions on their website. Compare your three measurements against the three numbers in their limit.

All three dimensions must be within the limit — not just two. An airline sizer frame is a rigid box, and your bag must fit inside it in all three directions.

Common airline carry-on limits for reference:

Airline	Carry-On Limit
American Airlines	56 × 36 × 23 cm
Delta Air Lines	56 × 35 × 23 cm
British Airways	56 × 45 × 25 cm
Lufthansa	55 × 40 × 23 cm
EasyJet (large cabin bag)	56 × 45 × 25 cm
Ryanair (paid cabin bag)	55 × 40 × 20 cm
Wizz Air (paid cabin bag)	55 × 40 × 23 cm

The depth dimension (third number) is the most restrictive and the one most often violated by bags marketed as "cabin size."

Step 8: Handling a Borderline Bag

If your bag measures within 1–2 cm of the limit, consider the following:

Airline strictness matters. Full-service carriers like British Airways or United rarely use sizer frames and have some tolerance for marginally oversized bags when the cabin isn't full. LCCs like Ryanair and Wizz Air use rigid sizer frames with no tolerance.

Redistribute the contents. If the bag is just over in one dimension because of a pocket full of heavy items, moving those items can reduce the protrusion.

Compress soft-sided bags. Some nylon bags can be compressed slightly. This is not reliable, but a bag that's 1 cm over on depth may just fit if the contents are compressed before boarding.

Pack a compliant personal item instead. If a bag is consistently over the carry-on limit by more than 2 cm, it's more practical to size down to a bag that definitely complies than to gamble.

Quick Reference: Key Numbers to Remember

Most restrictive free personal item (Ryanair): 40 × 20 × 25 cm
Typical full-service carry-on: 55 × 40 × 23 cm (approximately)
Wheels typically add: 2–4 cm to length
Handle housing typically adds: 3–6 cm to length
Exterior pockets typically add: 2–5 cm to depth

Measure once at home, record the numbers somewhere you can access at the airport (a photo in your phone works well), and you can board with confidence.