Ocean Freight Surcharges: BAF, CAF, PSS and GRI Explained

The contract rate was $2,600 per forty-foot box, and the invoice says $4,540. Somewhere between the two sit a bunker adjustment factor nobody recalculated, a peak season surcharge the contract excluded, and a general rate increase that landed on cargo already at the container yard. Freight buyers approve these lines every week because each one looks plausible on its own.

Ocean surcharges are not arbitrary, but each follows a different trigger: a fuel price, an exchange rate, a calendar window or a published tariff change. When every charge is tested against its own trigger and the contract wording, overbilled lines can be found and disputed before payment rather than written off. The US tariff rules in 46 CFR Part 520 supply the dates and notice periods that make those tests objective.

• What this guide explains: how BAF, CAF, PSS and GRI are built, what US tariff rules require of carriers, and how a service contract decides whether a surcharge applies at all.
• What it adds: a worked audit of one US and one Indian container, why surcharges raise Indian duty but not US duty, a traced billing error and contract clauses for the next tender.

How an ocean invoice is assembled from a base rate and add-ons

An ocean freight invoice is a base rate plus a stack of adjustments, each priced on its own basis: per container, per revenue ton or as a percentage of the base. Auditing it means separating the stack and testing each layer, because a total-only check cannot tell a correct BAF from an excluded PSS.

The US tariff rules treat the stack the same way. Under 46 CFR 520.2 an "assessorial charge", in the regulation's own spelling, is the amount added to the basic ocean freight rate, and 520.6(e) requires a carrier's tariff system to display the basic rate together with a list of all assessorial charges and surcharges that apply to the shipment parameters entered. A shipper can therefore rebuild the expected invoice from public data.

Ocean freight surcharge audits under 46 CFR 520.6(e) can start from the carrier's own tariff display, which must show the basic ocean freight rate and every applicable surcharge; a shipper rebuilding a 40-foot invoice from that display should reconcile each line within $1 of the billed amount.

Some surcharges are not the carrier's at all. Terminal charges, canal tolls and similar items collected on behalf of others follow special rules, and an NVOCC that passes a vessel operator's surcharges to its shipper is bound by a no-markup rule. The next section sets out those rules, because they decide which charges a shipper can challenge and on what date.

What 46 CFR Part 520 requires of a carrier's published surcharges

For cargo moving under a US tariff, an increase in any rate or charge, surcharges included, cannot take effect earlier than 30 calendar days after publication. That single rule, in 46 CFR 520.8(a)(1), is the strongest audit test a shipper has for GRIs and new or raised surcharges on US import and export lanes.

• Each charge stated separately: 520.4(a)(4) requires a tariff to state separately each terminal or other charge under the carrier's control and any rule that changes or determines the total charge.
• Thirty-day notice: 520.8(a)(1) bars a new rate, charge or change that increases a shipper's cost from taking effect earlier than 30 calendar days after publication; decreases may take effect on publication under 520.8(a)(4).
• Pass-through exception: 520.8(b)(4) lets changes in charges outside the carrier's control, where it only collects them, take effect on publication, and forbids marking them up above cost.
• Date that decides the rate: 520.7(c) applies the rates, charges and rules in effect on the date the cargo is received by the carrier or its agent, not the sailing or bill of lading date.
• NVOCC pass-through: 520.7(a)(3)(iv) lets an NVOCC cross-reference an ocean carrier's surcharges and GRIs only if it lists them by name and does not mark them up above cost.

General rate increases and new surcharges in a US ocean tariff cannot take effect earlier than 30 calendar days after publication under 46 CFR 520.8(a)(1), and 46 CFR 520.7(c) applies the charges in force on the date the carrier receives the cargo, so receipt records decide every timing dispute.

Part 520 is a US rule for carriers in US foreign commerce. India has no equivalent public tariff-filing regime that this article relies on, so on an India-China or India-Gulf lane the shipper's protection is the quotation and contract wording; the Indian angle that does carry regulatory weight, customs valuation, is covered later.

Service contracts: when a surcharge or GRI can reach a fixed rate

A filed service contract overrides the tariff for the cargo it covers, so whether a BAF, PSS or GRI applies depends on the contract's words. A rate written as "all-in" or "not subject to GRI" is protected; a rate "subject to tariff surcharges" imports whatever the tariff says at the time of receipt.

46 CFR 530.8(b) requires every filed service contract to state, among other terms, the commodity, the minimum volume or portion, the line-haul rate, liquidated damages if any and the duration. Section 530.8(c) adds that those terms may not be uncertain, vague or ambiguous, nor refer to terms not contained in the contract unless they are readily available to the parties and the Commission. A surcharge clause that points to "applicable surcharges" relies on that readily available tariff.

Our comparison of named account and FAK ocean rates covers how each contract type is filed and committed. This article stays with the surcharge clause, because the same contract can be watertight on the base rate and wide open on everything added to it.

Bunker adjustment factor: fuel price, lane factor and review period

A BAF moves the freight price with marine fuel cost, using a reference fuel price, a base price already inside the base rate, a lane-specific consumption factor and a review period. Every one of those four inputs must be named in the contract, or the BAF line cannot be checked.

Fuel cost became a larger and more visible surcharge after 1 January 2020, when the International Maritime Organization's limit on sulphur in ships' fuel oil fell from 3.50% to 0.50% mass by mass outside emission control areas, under MARPOL Annex VI regulation 14. Inside emission control areas the limit is 0.10%. Lower-sulphur fuel costs more, and carriers adjusted BAF formulas and low-sulphur surcharges to recover the difference.

Illustrative BAF and companion checks (contract-defined; carriers' own formulas differ)

BAF per FEU   = round_to( (P_ref - P_base) * k_lane , 10 )
  P_ref  = average price of the named fuel grade over the reference
           period (USD per tonne), from the index the contract names
  P_base = fuel price already included in the base ocean rate
  k_lane = tonnes of fuel attributed to one FEU on this lane
  Worked: (620 - 450) * 3.18 = 540.60  ->  billed $540

CAF           = r_caf * base_rate          (only if the contract allows)
PSS applies   = window_start <= receipt_date <= window_end
GRI applies   = receipt_date >= effective_date
                AND effective_date >= publication_date + 30 days   (US tariff)
                AND contract rate is not fixed against GRIs

Tolerance: flag any BAF line differing from the table by more than $5 per FEU,
or any PSS/GRI line where receipt_date is missing.

Road freight buyers will recognise the idea from diesel fuel surcharges, but the mechanics differ. Our guide to reproducible fuel surcharge calculation covers weekly index brackets on truck bills; ocean BAF usually changes monthly or quarterly, uses a marine fuel reference and a lane factor, and is published by the carrier rather than read from a government index.

Currency, peak season and general rate increase charges compared

CAF, PSS and GRI are often listed together, yet they answer different questions: CAF protects a carrier against currency moves, PSS prices a seasonal capacity squeeze, and GRI raises the base rate itself. Each needs a different audit test, so treat them as three separate checks.

• CAF compounding risk: because CAF is a percentage, it should apply to the base rate only; a CAF calculated on base plus BAF and PSS overcharges every time the other lines rise.
• PSS window disputes: peak season charges are announced with start dates that slip; the date that counts on a US tariff shipment is cargo receipt, not loading.
• GRI that never sticks: carriers announce GRIs that the market later erodes, so an invoice may carry the full increase while the spot rate the buyer could have booked is lower.
• Exchange rate on local invoices: when a USD freight bill is invoiced in rupees, the agent's conversion rate works like a hidden CAF and should be checked against a stated reference.

Auditing one container invoice in dollars and rupees

The worked audit below takes one US import under a service contract and one Indian import bought FOB through a forwarder. All figures, including the contract terms, fuel prices and exchange rates, are illustrative; they show the test applied to each line rather than any carrier's current charges.

Two different lessons sit in the table. On the US lane the money is in the contract: $1,400 of the $4,540 bill was never payable, and the evidence is the contract clause plus the receipt date. On the Indian lane every accepted surcharge also raised the duty base, so ₹6,737 of basic duty and surcharge became permanent cost, while the ₹12,237 of IGST is recoverable only through the importer's input tax credit.

Why surcharges raise Indian customs duty but not the US duty base

Ocean freight, surcharges included, sits outside the US customs value but inside India's. That single difference means a BAF or PSS dispute is purely a freight-cost question for a US importer, while for an Indian importer each surcharge dollar is also taxed at the border.

In the US, 19 U.S.C. 1401a(b)(4)(A) defines the price actually paid or payable as exclusive of transportation, insurance and related services incident to the international shipment to the place of importation. In India, the proviso to Section 14 of the Customs Act includes costs of transportation to the place of importation in transaction value, and Rule 10(2) of the 2007 valuation rules adds the cost of transport, insurance and associated charges up to that place.

Indian customs value includes ocean freight surcharges such as BAF, CAF, PSS and GRI as cost of transport to the place of importation under Customs Act Section 14 and valuation Rule 10(2); in the worked example, $696 of surcharges raised duty and IGST paid at the border by about ₹18,975.

The boundary sits at the Indian customs station. Jawaharlal Nehru Custom House Public Notice 132/2017 explains that after Notification 91/2017-Customs (N.T.), loading, unloading and handling charges for delivery at the place of importation are no longer added, so destination terminal handling stays out. Our import landed cost guide for India works through the full duty stack, including the exchange rate fixed on the date the bill of entry is presented.

A peak season surcharge charged on cargo received too early

Timing errors are the most winnable surcharge disputes, because the carrier's own receipt record settles them. The illustrative trace below follows an NVOCC tariff shipment into the US, with invented document numbers, where the billing system keyed the surcharge to the wrong date.

• 1 July, 10:00 ET: the NVOCC publishes a $600 per FEU peak season surcharge in its tariff, effective 31 July, which is 30 calendar days after publication as 520.8(a)(1) requires.
• 29 July, 15:40 local time: container TGHU 7720418 is received at the origin container yard; gate-in record GI-2207 shows the carrier's agent taking custody.
• 2 August, 21:10 local time: the container is loaded and bill of lading HBL-55120 is dated 2 August, after the surcharge took effect.
• 18 August, 09:30 ET: invoice INV-55120 includes the $600 PSS, because the NVOCC's billing system rates by bill of lading date.
• 20 August, 14:00 ET: the shipper disputes the line with GI-2207 and 46 CFR 520.7(c), which applies charges in effect on the date cargo is received; the NVOCC issues a credit note for $600.

The controlled version keeps the receipt date on every shipment record and lets the rating engine price surcharges from that date. Where receipt and loading straddle an effective date, the audit queue receives the shipment automatically with the gate-in record attached, so nobody has to notice the timing by reading the invoice.

Surcharge checks to automate and calls a freight buyer keeps

Arithmetic and date tests on surcharges should run on every invoice without exception. Interpreting a vague contract clause, accepting a new charge type or deciding whether to escalate a carrier dispute stays with a named buyer, because each one changes the commercial relationship.

Contract clauses and a tender checklist for ocean surcharges

Most surcharge disputes are decided by wording agreed at tender. Settle each surcharge's inclusion, formula, review period and notice in the contract, and the audit becomes a lookup rather than a negotiation each time an invoice arrives.

For related freight cost and contract topics, browse the Logistics and Supply Chain collection. Our note on rate card effective dates covers versioning of the base rate itself. To automate receipt-date rating and surcharge checks in your freight audit, describe your lanes and contracts in our request for proposal form.