Bunker Adjustment Factor (BAF)

"Bunker" is a ship's fuel. The bunker adjustment factor (BAF) lets a carrier move its fuel cost up or down without renegotiating the base freight rate: the base rate stays put and the BAF is recalculated on a schedule. It is charged per container, by container type and trade lane, and the name varies by carrier. Maersk calls it BAF; Hapag-Lloyd's equivalent is the Marine Fuel Recovery (MFR) surcharge.

How it is calculated

Carriers tie BAF to a published fuel price index. Maersk, for example, uses Platts' index for 0.5% sulfur fuel oil (VLSFO): the levels effective January 1, 2026 were based on average prices from August 26 to November 25, 2025, and the previous quarter's on the three months before that. A formula-based BAF can fall as well as rise.

IMO 2020 and low-sulfur fuel

Since January 1, 2020, MARPOL Annex VI has limited the sulfur content of ships' fuel oil to 0.50% m/m outside emission control areas, down from 3.50%, and to 0.10% inside them. That is why Maersk's BAF, for example, is indexed to compliant 0.5% sulfur fuel oil.

The tariff rules in US trades

• BAF is a tariff charge. Common carriers and NVOCCs must publish their rates and charges in tariffs open to public inspection (46 CFR 520.3)
• An increase cannot take effect until 30 calendar days after it is published; a decrease can take effect on publication (46 CFR 520.8)
• Cargo under a service contract or an NVOCC negotiated rate arrangement is priced by that agreement's terms, including how surcharges apply; an NRA must be agreed in writing before the cargo is received (46 CFR 532.5)

Common mistakes

• Comparing an all-in rate with a base rate that has BAF to add
• Assuming a quote's BAF is fixed: unless the quote says so, the level in force on the tariff's reference date applies
• Missing other fuel-related lines, such as low-sulfur or emergency fuel surcharges some carriers add separately

BAF sits alongside the GRI, the peak season surcharge and terminal handling on a FCL quote. Our ocean freight quotes state whether each surcharge is included or extra.