IATA CO2 Connect

IATA CO2 Connect is a CO2 emissions calculator designed for commercial passenger flights. This solution supports airlines, travel management companies, travel agencies, integrators, and Global Distribution Systems (GDS) to easily integrate accurate CO2 emissions calculations into their operations. 

Built on the industry-standard IATA Recommended Practice 1726, IATA CO2 Connect leverages a per-passenger emissions calculation methodology developed in collaboration with airlines and other aviation industry stakeholders. Unlike many other calculators that rely on theoretical data models, IATA CO2 Connect uses real operational data from airlines, including aircraft type-specific fuel consumption and airline-specific load factors, ensuring unparalleled accuracy and reliability.  

The calculation can be viewed as a three-step process: 

1. Calculation of total CO2 emissions for a given flight based on the fuel consumption. 
2. Proportional distribution of CO2 emissions between passenger and cargo payload based on weight.
3. Allocation of CO2 emissions among passengers considering expected aircraft occupancy and cabin classes. 

Passenger CO2 emissions in IATA CO2 Connect are calculated in line with the IATA Recommended Practice RP1726 adopted by IATA’s Passenger Service Conference in March 2022. This methodology was created through collaboration between airlines, leading aircraft manufacturers, and international standard-setting bodies. 

There are three main differentiation points between the IATA CO2 Connect calculator and other calculators:  

1. Actual airline data is used for aircraft type-specific fuel consumption, passenger load factors, and belly cargo weight. Other calculators model fuel consumption or provide generic estimates using theoretical data models and assumptions and not necessarily considering all aircraft models. Hence, they may not consider airline operational efforts to reduce fuel consumption, and thereby per-passenger CO2 emissions, and as such lower the accuracy of their results. 
2. A time-based approach is used as opposed to a distance-based one which is more appropriate for air transport versus other modes of transport. The emissions of a flight can vary significantly depending on the direction of travel between two airports, and using a time-based approach captures these variations more accurately. For example, flights between North America and Europe tend to take longer westbound than eastbound, due to the prevalent winds, and IATA CO2 Connect emissions estimates reflect this. 
3. There is alignment between passenger and freight transport in CO2 emissions calculations. Many CO2 emissions calculators are either passenger-specific with no cargo/freight considerations or freighter calculators without passenger weight/payload considerations.  IATA CO2 Connect has aligned calculations for passenger and air cargo transport.   

Factors which influence the CO2 footprint of an individual’s air travel can generally be divided into two categories: factors which influence the emissions of a flight, and factors which influence the allocation of the aircraft’s emissions to individual passengers. 

The key determinant of emissions of any given flight is fuel consumption, driven by factors such as aircraft type or flight duration – the latter often influenced by weather and airspace efficiency. Generally, larger and heavier aircraft tend to emit more on a given route. However, their higher capacity may result in lower per-passenger emissions. 

In order to accurately allocate the CO2 emissions per passenger, the weight ratio between passengers and cargo must be determined. The larger the share of cargo weight, the more emissions are allocated to it. 

Once the share of the flight’s emissions attributed to all passengers is known, the allocation between individual passengers depends on: 

1. The total number of seats on the aircraft, as well as their distribution between different cabin classes; and
2. How full the aircraft is, i.e., how many seats are occupied by passengers (passenger load factor). 

A larger number of passengers onboard – whether through a larger number of seats or a larger portion of seats being filled – tends to result in lower CO2 emissions allocated to an individual passenger. 

Please refer to the data model documentation here. 

Do you have any additional questions?  If you have questions not answered in the FAQ section, please contact the IATA CO2 Connect team. 

Please refer to the data model documentation on page 10, here.  

We are constantly building on the accuracy of the calculator which includes the aircraft type selection.  If you have noticed any issues, or have questions not answered in the FAQ below, please contact the IATA CO2 Connect team.  Please make sure to include all relevant information (and screen-shots, as applicable).

Passenger CO₂ emissions are calculated in line with the IATA standard recommended practice RP1726. In practical terms, the calculations are performed in three key steps:

1. Calculating Total CO₂ Emissions of a Flight:

a. A flight schedules database is queried based on the chosen route:

• If a match is found, up to 10 aircraft types are available for user selection. By default, the most used aircraft type is pre-selected.
• If no match is found, the (great circle) distance between the origin and destination airport is calculated based on the route. Up to 10 aircraft types that are flown on similar distances are available for user selection. By default, the most used aircraft type is pre-selected.

b. Total flight time (block time, from gate to gate) is based on the route and the chosen aircraft.

• Scheduled flight times may vary on a specific route, even if they are operated by the same aircraft type. In these instances, a weighted average flight time is used.

c. The IATA CO2 Connect calculator is time-based. Hence, the flight time is multiplied with a fuel consumption factor (in kg/min) specific to the chosen aircraft type. This gives the total fuel consumption of a flight.

d. The fuel consumption is multiplied by the ICAO CORSIA CO₂ emissions factor for jet kerosene of 3.16, resulting in the total CO₂ emissions for the flight.

2. Allocating CO₂ Emissions Between the Passengers and (Belly) Cargo: 

a. Projected number of passengers for a flight is calculated based on the cabin configuration of the selected aircraft type and the passenger load factor.

b. Total weight of all passengers (and their baggage) is calculated by multiplying the number of passengers by the standard weight of 100kg.

c. Projected (belly) cargo weight is determined based on the aircraft type.

d. A ratio of total passenger weight and total (passenger + belly cargo) weight is calculated.

e. The total CO₂ emissions for the flight are multiplied by this ratio, resulting in the share of the flight’s emissions that is attributed to all the passengers.

• The difference between the total CO₂ emissions for the flight, and those that are attributed to all the passengers, are the CO₂ emissions allocated to belly cargo.

3. Allocating CO₂ Emissions to Individual Passengers Based on Cabin/Travel Class:

a. For each of the cabin classes (economy, premium economy, business, or first), the expected number of seats in the cabin class is determined, depending on the selected aircraft type.

b. CO₂ emissions are allocated to passengers, depending on the cabin class, based on the CO₂ emissions of all passengers and the ratio of [cabin class factor of chosen class] and the [sum for all classes of (number of seats in class * cabin class factor)]. For added clarity, please refer to the calculation example for economy class.

c. CO₂ emissions are displayed for a passenger in the cabin class selected as the calculator input.

Yes, there is a calculation example. Please see below:

Input:

Please see the calculation steps in the following table with formulas, including actual numbers in brackets. Calculation steps refer to the previous question (“How are CO₂ emissions calculated?”). The numbers used in the example are only for illustration purposes and do not reflect a real example. Should you try the exact same example with the IATA CO2 Connect calculator you will get the correct result.

The calculator derives time based on the route, as described in steps 1a-1b.

The following data is used:

• Airline-contributed fuel consumption data by aircraft type
• Airline-contributed belly cargo data by aircraft type
• Cabin configurations, i.e., seats by travel class, by aircraft type from a fleets database
• Passenger occupancy data (i.e., load factors) from IATA traffic database
• Flight duration from schedules per route, per aircraft type, from a schedule database

No. IATA CO2 Connect provides calculation results in different formats such as API or Flat File which can be integrated into e.g. a website, booking flow, or corporate reporting, based on the business need. 

Existing audit/verification procedures are leveraged, such as data verification for CORSIA. Additionally, IATA conducts its own statistical validation of all input data received from airlines. More information can be found here: Data model documentation. 

Currently, 75 different (IATA designator) aircraft types are covered in the data model, representing more than 98% of the current global passenger fleet.

Some elements such as airline fleet information are updated on a monthly basis, while others, such as airline-specific fuel consumption, may be updated annually to ensure sufficient validation processes have taken place. The underlying data may also be updated more frequently if deemed necessary, e.g., when new aircraft types are being introduced. 

Fuel consumption data per aircraft type is updated by airlines on an annual basis, using preceding year’s data.  Current operational data such as load factors is based on 2023 data. 

Currently, a single fuel burn rate (kg/min) is used for all flights on a given aircraft type, regardless of its duration. While this causes some loss of accuracy, particularly for flights outside an aircraft’s usual operations (e.g., a widebody used on a very short flight), the impact is marginal, especially after considering other sources of uncertainty in the pre-flight CO2 estimates. Nevertheless, we are considering the use of differentiated fuel burn rates depending on the duration of the flight in a future release of the calculator. 

Yes, this feature will be part of a later enhancement to the calculator.

IATA has recently released IATA - SAF Accounting & Reporting Methodology providing a comprehensive framework ensuring an accurate, consistent, and transparent accounting of emission reductions associated with SAF use. In 2025, IATA CO2 Connect will account for SAF reductions on a network-wide basis and later look into implementing SAF reductions on an origin-destination basis. 

In line with the Recommended Practice RP1726 for per-passenger CO2 emissions calculations, carbon offsets are not considered in the estimates. 

IATA is closely engaging with ICAO’s Committee on Aviation Environmental Protection (CAEP), research institutions and industry stakeholders to monitor developments in measuring non-CO2 emissions from conventional fuel and SAF. In line with the recommended practice RP1726, RFI and non-CO2 effects are not included in the calculator. As soon as consensus has been reached by the global scientific community in terms of the value(s) that must be applied, the IATA CO2 Connect calculator will be adapted accordingly. Should you be interested in more background on this topic, please refer to the RP1726 methodology.

In line with the Recommended Practice RP1726, the IATA CO2 Connect calculator uses an emissions factor of 3.16 for jet kerosene, which includes the CO2 emissions related to jet kerosene combustion. This is based on ICAO Annex 16, Volume IV. Upstream emissions (i.e., those related to production and transport of the fuel) are therefore not included in the estimates.

IATA is developing an IATA CO2 Connect for Cargo calculator which will provide per shipment emissions calculations. The calculator is currently in pilot stage to be released later in 2025.

Currently, it is not possible to compensate CO₂ emissions via the IATA CO2 Connect calculator. However, we are developing such a solution, and a compensation feature will be added to IATA CO2 Connect calculator in 2023.