Carry-On Bag Fit Calculator

How this carry-on bag fit calculator works

Airlines restrict carry-on baggage to ensure bags fit safely in overhead bins and to keep boarding practical. This calculator compares your bag’s length, width, height (in centimeters) and weight (in kilograms) against typical published carry-on limits for the selected airline. You’ll get a clear pass/fail result and, when relevant, which measurement(s) exceed the limit.

What the calculator checks

• Individual dimensions: length, width, and height each must be at or under the airline’s maximums (when provided).
• Linear dimension (sum): some policies reference a total size; this is often called “linear dimensions.”
• Weight: if the airline publishes a carry-on weight cap, your entered weight is checked against it.

Formulas used

The calculator uses straightforward geometry and comparisons:

• Linear dimensions (total size): S = L + W + H
• Volume (approximate): V = L × W × H

Math notation:

Important: Most airline rules are based on maximum allowed dimensions (e.g., 55 × 35 × 23 cm). Even if your total S is small, you can still be rejected if one side is too large for the sizer or bin.

How to measure your bag (so the result matches reality)

1. Place the bag upright on a flat surface.
2. Measure the largest external length, width, and height.
3. Include wheels, handles, and rigid side pockets if they protrude—airline sizers typically do.
4. If the bag is soft-sided, measure it in a reasonably “packed” state, since overstuffing can change the outer size.

Units on this page are cm and kg. If you measured in inches or pounds, convert before entering values.

Interpreting the results

After you enter your measurements and choose an airline, the calculator can return outcomes like:

• Fits: your length/width/height are within the listed maxima, and weight (if checked) is within the cap.
• Doesn’t fit: at least one dimension or the weight exceeds the airline’s typical limit.
• Borderline: if you’re within a few millimeters/0.1 kg, real-world enforcement may still differ because of measurement method, sizer tolerances, and how full the bag is.

Worked example

Assume your carry-on measures:

• Length L = 55 cm
• Width W = 35 cm
• Height H = 23 cm
• Weight 8 kg

Compute quick reference values:

• Linear dimensions: S = 55 + 35 + 23 = 113 cm
• Volume: V = 55 × 35 × 23 = 44,275 cm³ (useful for comparing packing capacity, not airline compliance)

If the selected airline’s limit is at least 55 × 35 × 23 cm and its carry-on weight cap is ≥ 8 kg (or no weight cap is enforced/published), the calculator will mark the bag as fitting. If you changed only one value—say height to 28 cm—the tool would flag height as exceeding the maximum, even if the total S remains reasonable.

Typical carry-on limits: quick comparison

The specific numbers vary by route, fare, and aircraft. The table below is meant as a high-level comparison of what you’ll often see across carriers, which is why the calculator emphasizes checking each dimension and weight separately.

Limitations and assumptions (read before relying on the result)

• Policies change: airline baggage rules can change without notice. Treat the calculator as a planning aid, not an official guarantee.
• Route, fare class, and ticket type matter: basic/standard/premium fares may allow different cabin bags; some routes have stricter limits.
• Aircraft differences: regional aircraft and smaller overhead bins can reduce what is accepted even within the same airline.
• Measurement method: airlines typically measure the outermost points, including wheels and handles, using a rigid sizer. Soft-sided bags can “bulge” and fail even if tape-measured dimensions look compliant.
• Enforcement varies: gate agents may enforce rules more strictly on full flights or for certain boarding groups.
• Weight handling: if a weight limit is not provided for an airline in the tool, the calculator may effectively treat it as “not checked.” Always confirm the current rule if weight is a concern.
• Personal item is separate: many airlines allow (or require) an additional personal item with its own size limits; this calculator focuses on the carry-on bag.

Practical tips if you’re slightly over

• Remove rigid accessories (hard cases, external organizers) that add bulk.
• Shift dense items to a personal item (if allowed) to reduce carry-on weight.
• Use compression straps cautiously—over-compressing can make a bag too thick and more likely to fail a sizer.
• If you are very close to the limit, prefer a bag with recessed wheels and minimal handle protrusion.