Why is there a weight limit for carry-on baggage? Six questions and answers about weight and flying

1. Why is there a weight limit for carry-on baggage when a heavy bag takes up the same amount of space as a lighter bag in the cabin?

The safe operation of flights requires that the weight of the aircraft is known so that a weight-based load and balance calculation can be made for the flight. Each aircraft has a maximum takeoff weight for a safe takeoff. The weight of the aircraft also impacts the range the aircraft can fly.

The weight includes the weight of the aircraft itself, the weight of fuel, the weight of baggage and cargo in the hold, the weight of catering on board, the weight of water tanks in the toilets, and the weight of customers on board. The airline knows the weight of all elements aside from the weight of the passengers on board. Airlines use average passenger weights, based on standards defined by aviation safety authorities. Average passenger weights include the weight of carry-on baggage customers have onboard. 

2. Why don’t you reassess the baggage allowance included in Economy and Premium Economy Class tickets as well?

In Economy and Premium Economy Class, the weight limit of 8 kg remains unchanged. 8 kg is a common weight limit with many airlines, and it has been our weight limit for years in Economy Class. 

Increasing the weight limit for carry-on baggage always requires authority approval, and a larger-scale increase would require an analysis of the impact of increasing weight on the load and balance calculations that are required for safe operations.  We are currently carrying out this assessment, and it will be completed in 2024.

3. Why does the carry-on baggage weight limit vary from airline to airline?

Carry-on baggage weights are included in the average passenger weights airlines use for aircraft performance calculations. Each airline defines its own weight limits, based on the aircraft they use, the routes they fly, the characteristics of the destination airports, including runway length, their passenger profiles (leisure/business), and the airline’s business decisions. Finnair's weight limits are 8kg in Economy and Premium Economy Class and 12 kg in Business Class.

You can check your baggage allowance via Finnair mobile app and in the Manage booking service.

4. How is the weight of passengers estimated?

The average weights used by airlines are based on standard weights defined by authorities, in Europe, the European Aviation Authority (EASA). Weight limits are updated from time to time, and the latest EASA-commissioned study on average air passenger weights is from 2022.  For the study, volunteering air travellers were weighed with their carry-on baggage at different European airports. 

Finnair has also conducted its own research; In 2017, we weighed volunteering customers at the airport with their carry-on baggage to get a better idea of the direction in which average weights have developed. The results of this study were used to define the average passenger weights Finnair uses. 

The weighing of customers for defining average passenger weights is always voluntary, and the results are processed anonymously. The average weight is affected by many things: business travellers often carry more carry-on baggage than leisure travellers, and in winter, people wear heavier clothes, which also affects the weight.

Each airline makes its own average calculations based on the authority's standard calculations. The weight of carry-on baggage is calculated according to the average weight of the passenger.

5. Can the weight of the aircraft somehow affect the flight?

The weight of the aircraft impacts the flight's operation. When flying with our smallest aircraft type, ATRs, the crew sometimes asks customers to move to another seat due to the balance of the aircraft. Sometimes baggage must be left behind due to weight limits, and there are also cases where the airline has had to limit the number of customers on a flight. Weight can become an obstacle to a safe takeoff, for example, in challenging wind conditions or when the runway is slippery. A heavier plane needs more runway length to take off, as to lift heavier mass into the air, the wing needs a higher speed at takeoff, and, therefore, longer acceleration. 

Weight limits for baggage are in place so that we can avoid situations where baggage or customers cannot be taken on a flight due to weight limitations – we want to avoid these kinds of situations that disrupt our customers’ journey. Safety is always our top priority, and every flight is operated accordingly.

6. What else should I know about the weight of the aircraft?

Weight has a direct effect on the flight’s fuel consumption and its CO2 emissions. A lighter aircraft consumes less fuel and therefore produces less carbon dioxide emissions. We constantly strive to reduce the weight of our aircraft, for example, by choosing lighter materials for the cabin (such as seats, mats and trolleys) when possible and by optimising the amount of potable water on board. 

You, too, can influence the carbon dioxide emissions of your flight by packing lighter. If every Finnair customer had left two kilos of baggage at home in 2022, the saved fuel would have been enough to fly 20 times from Helsinki to Tokyo.