How Overhead Buddy Checks Carry-On Size Limits

Airline carry-on size limits are not standardized. Each provides their own dimensions, and even small differences can determine whether your bag fits in the overhead bin.

Overhead Buddy was built to eliminate guesswork by comparing your luggage dimensions against official airline carry-on policies in one place.

Step 1: Enter Your Bag Dimensions

Start by entering your bag's outer dimensions, including wheels, handles, and protruding pockets.

You can input measurements in inches or centimeters. The tool automatically standardizes conversions for accurate comparison when applicable.

Bags, especially soft-sided ones, should be measured fully packed as expansion can affect fit.

If you do have a soft bag, check the "soft bag" toggle, as this will give you more tolerance for the bag's overall height.

Step 2: Choose Your Airline(s)

You can:

• Check a single airline
• Compare multiple airlines at once
• Check against all supported airlines

This is especially useful if:

• You have connecting flights
• You're flying different airlines outbound and return
• You haven't booked yet and want flexibility

The multi-airline comparison highlights which carriers allow your bag and which do not.

Step 3: Understanding the Results

Your bag is measured against the carry-on and personal item limit of the selected airline. Each airline returns one of three results:

Fits

Your bag dimensions fall within the airline's published carry-on size limits. Based on official measurements, it qualifies as a standard carry-on.

Maybe Fits

Your bag is extremely close to the limit or falls within rounding tolerance between inches and centimeters.

For example, an airline may publish a length of 55 cm, which converts to 21.65 inches. They may be rounding up to 22 inches, the most common carry-on length.

Minor rounding differences can create borderline scenarios. Enforcement may vary by airport and flight load.

If your bag returns "Maybe Fits," consider checking with the airline directly or using a slightly smaller bag for full certainty.

Doesn't Fit

At least one dimension exceeds the airline's maximum published carry-on size by over 1 inch (2.54 cm).

You may be required to gate-check the bag or pay an additional fee.

Personal Item Dimensions

Where available, Overhead Buddy also displays personal item size limits.

Some airlines do not clearly publish personal item dimensions. In those cases, only confirmed carry-on limits are shown.

When there is no personal item dimension, we use a default dimension of 18×14×8 in (45.72 × 35.56 × 20.32 cm) to determine if it will fit.

Always verify your airline's current policy before traveling.

Fare-Based Carry-On Restrictions

Certain airlines adjust carry-on allowances depending on fare type.

For example:

• United Airlines Basic Economy may restrict full-size carry-on bags on certain routes.
• Delta Air Lines allow a carry-on and personal item for all ticketed passengers.

Overhead Buddy highlights standard published size limits, but fare-based restrictions may still apply.

While we continue to add fare types for major airlines, it's recommended to review your specific fare class details on the airline's official website before departure.

Inches vs Centimeters and Rounding

Airlines sometimes publish dimensions in only centimeters while others use inches. When converting between systems, minor rounding differences can occur.

For example: 55 cm equals 21.65 inches, not exactly 22 inches.

Overhead Buddy standardizes conversions to ensure fair comparison, but borderline bags may still be subject to enforcement discretion.

Reminder: This is a Tool, Not a Final Answer

Overhead Buddy compares your bag against published airline size limits. It can give you a really good idea if your bag will fit or not.

Final acceptance is always at the discretion of airline staff at the airport.