International flights (non-UK legs, economy): carbon footprint per passenger-km (with RF)

DESNZ publishes a separate factor for flights that neither start nor end in the UK — the onward legs of multi-stop itineraries. The economy figure, live below with radiative forcing, is slightly lower per km than the UK long-haul factor because these legs skew toward the longest, most cruise-efficient sectors.

Use it for the New York–Los Angeles or Singapore–Sydney legs of a trip that began in Britain: our travel calculator applies the right category from the airports you enter. The same cabin-class multipliers apply — premium cabins on these legs carry 1.6 (premium economy) to 4 times (first) the economy footprint.

Worked example

New York to Los Angeles, one way (~3,944 km GCD + 8%): 4,260 × 0.10916 = 465 kgCO2e.

Measure your own with the free travel calculator.

Frequently asked questions

When does the international factor apply instead of long-haul?

For legs that neither depart from nor arrive in the UK — the onward segments of multi-stop trips. UK-touching legs use the domestic, short-haul or long-haul factors instead.

Related factors

• Long-haul flights (economy)
• Business-class flights (long-haul)
• Short-haul flights (economy)