What is ocean freight?
Ocean freight is cargo carried by container ship between seaports. One vessel moves thousands of containers on a single sailing, and that scale is why the cost per unit is lower than any other mode. You buy it in two shapes:
- FCL, full container load: a flat rate for a whole 20 ft, 40 ft or 40 ft high cube container, whether or not you fill it, up to the container payload limit.
- LCL, less than container load: your pallets share a container with other shippers. The forwarder consolidates at origin and deconsolidates at destination, which adds handling time on both ends and more touches on your cartons.
Ocean freight meaning, in one line: the sea leg only. A quote marked port to port covers the vessel and very little else. Origin trucking, export clearance, terminal handling, customs entry, duty and the delivery run into your warehouse sit outside it unless the quote says otherwise. Two ocean quotes for the same lane can look nothing alike until you line up exactly what each one includes, which is the whole job of a forwarder. If that role is new to you, start with what freight forwarding is.
What is air freight?
Air freight is cargo carried in the belly of a passenger aircraft or on a dedicated freighter, then handled through air cargo terminals at both ends. Three products get called air freight and they price very differently:
- General air cargo: airport to airport, booked through a forwarder who consolidates your cartons with other shippers. Cheapest of the three, and the one most brands mean.
- Air express: the integrators running door to door on their own network. Fastest and simplest, usually priced with a tighter volumetric divisor, so bulky cargo is punished harder.
- Charter: you buy the aircraft or a block of it. A peak season and crisis tool, not a replenishment plan.
Air freight vs ocean freight: side by side
| Air freight | Ocean freight | |
|---|---|---|
| Transit profile | Typically days once the cargo is uplifted, plus terminal handling and clearance at both ends | Typically weeks on the water, plus port dwell, rail or drayage inland |
| Cost basis | Per chargeable kilogram | FCL: flat rate per container. LCL: per revenue ton |
| Chargeable weight rule | Greater of gross weight or volumetric weight, using the carrier divisor | LCL: greater of cubic meters or metric tons. FCL: container size, capped by payload |
| Best fit cargo | High value per kilogram, compact, urgent, launch and bridge quantities | Dense or bulky, low value per kilogram, planned replenishment, bulk components |
| Capacity ceiling | Limited by aircraft door and pallet height and by weight per unit load device | Whole containers. Heavy, tall and oversized cargo is far easier to move |
| Restricted cargo | Tight acceptance on lithium batteries, aerosols, flammables, magnets and pressurized goods | More accommodating, still governed by dangerous goods declarations and stowage rules |
| Schedule risk | Missed uplift and peak season capacity crunches, but recovery is quick | Rollings, blank sailings, port congestion, canal and weather disruption |
| Emissions per ton mile | Highest of any common mode | Lowest of any common mode |
| Insurance exposure | Short time at risk, fewer touches, but carrier liability is capped by convention | Weeks at risk, more handling, plus general average exposure at sea |
| Transport document | Air waybill, a receipt and contract, not a document of title | Bill of lading, which can be negotiable and may be required to release the cargo |
Chargeable weight: the number that decides your invoice
Almost every unpleasant freight surprise traces back to this. Carriers do not bill what your scale says. They bill whichever is greater, weight or space, because space on an aircraft or in a container is the scarce thing.
How air freight chargeable weight works
Volumetric weight is length times width times height in centimeters, divided by a divisor the carrier sets. General air cargo commonly uses 6000, express couriers commonly use 5000, and some imperial rate sheets express the same idea as cubic inches per pound. Confirm the divisor on your own rate sheet before you build a model on it.
A worked example. A carton measuring 60 by 40 by 40 cm is 96,000 cubic centimeters. At a 6000 divisor that is 16 kg of volumetric weight. If the carton actually weighs 9 kg, you pay for 16. Across 40 cartons you are paying for 280 kg of air. That single gap is why a quote that looked affordable per kilogram lands as an invoice nobody planned for.
The fix is packing density, not negotiation. Right size the master carton, cut void, and stop shipping half empty boxes across an ocean or a sky. Our notes on shipping box sizes and net weight vs gross weight cover the measurements your forwarder will ask for.
How ocean LCL charges volume
LCL is priced per revenue ton, also called a freight ton or W/M, meaning weight or measurement. The rule: you pay on whichever is greater, one cubic meter or one metric ton. An 8 CBM shipment that weighs 1.2 metric tons bills as 8 revenue tons. A 2 CBM shipment of tile weighing 3 metric tons bills as 3. Most consumer goods are volume driven, so cubic meters is the number to watch.
Why FCL behaves differently
FCL is a flat rate for the box, so your cost per unit falls with every extra case you fit inside. The two limits are cubing out, running out of space before you run out of allowed weight, and weighing out, hitting the payload limit first with liquids, glass or hardware. Road weight rules at destination also cap what can legally leave the port on a chassis, so a container that loaded fine overseas can be illegal to haul here.
Air freight vs ocean freight cost: what actually moves the number
Rates on both modes move constantly with capacity, fuel and season, so treat any number you read online as stale. What is stable is the list of things that change your quote:
- Lane and direction. Trade imbalance means the same route can price very differently each way.
- Season. The weeks before Chinese New Year, Golden Week and the Q4 retail peak tighten both modes at once.
- Service level. Consolidated versus direct, deferred air versus next flight out, standard sailing versus premium guaranteed space.
- Surcharges. Fuel, security, peak season, congestion and currency adjustments ride on top of the base rate.
- Origin and destination charges. Terminal handling, documentation, filings on US imports, customs entry, bonds, drayage, chassis and detention.
- Free time. Demurrage and detention start the moment free days run out, and they are the fastest way to turn a good ocean rate into a bad one.
Compare landed cost per sellable unit, never the freight invoice alone. Take the full door to door cost including duty, divide by units that can actually be sold, and put that next to your unit margin. See how forwarder pricing is built for the line items that belong in that math.
How to choose air or ocean, shipment by shipment
This is a per purchase order decision, not a company policy. Four questions settle almost every case.
- Value density. Compare freight cost per kilogram to revenue per kilogram. Supplements, small electronics accessories and apparel absorb air. Glassware, liquids, pet food and furniture do not.
- Cost of the stockout. Add lost margin, lost marketplace rank and ad spend still running to an unavailable listing. When that total beats the air premium, air is the cheap option. See what a backorder really costs you.
- Working capital. Ocean parks weeks of inventory in transit. Air shortens the cash cycle and lets a smaller safety stock hold the same service level, which matters most for a brand growing faster than its forecast.
- Calendar. Factory shutdowns, peak season and holiday promotions decide when a slow mode stops being viable, regardless of what the rate says.
Splitting one purchase order between air and ocean
Experienced importers rarely pick one mode for a whole PO. They cut it:
- Bridge quantity by air, balance by sea. Air only enough units to cover demand until the vessel lands. You pay the air premium on a fraction of the order instead of all of it.
- Launch by air, replenish by sea. Prove sell through on a small air shipment, then commit to a container once the demand signal is real.
- Air the winners, sail the tail. Inside a mixed PO, the two or three SKUs carrying the revenue justify air. The rest almost never do.
- Air into the marketplace, sail into reserve. Send the air portion straight into an inbound plan while the ocean balance lands at a 3PL as reserve stock, then gets prepped and forwarded on demand. That pattern is covered in detail in shipping from China to Amazon FBA.
Splitting only works if someone is watching both legs against one demand plan. Two shipments arriving three weeks apart with no receiving plan behind them creates the stockout you were trying to avoid.
What neither freight quote usually includes
- Customs entry, duty and any tariff exposure on your classification.
- The domestic leg from port or airport to the warehouse, whether that is drayage, LTL or a full truckload.
- Cargo insurance on invoice value. Carrier liability is capped by international convention at a level far below what your goods are worth, which is the point of separate cargo cover.
- Demurrage, detention and warehouse storage once free time expires.
- Receiving, palletizing, labeling and marketplace prep at destination, which is where FBA prep and warehousing pick the shipment up.
How RitePrep handles air and ocean freight
RitePrep runs its own Austin, Texas warehouse and has since 2020, with 99.9 percent pick accuracy and orders shipping nationwide. International freight is delivered through our partner Eleevate Logistics, covering ocean FCL and LCL, air freight, import and customs coordination, cargo insurance and inventory inspection, while the domestic leg is dispatched through The Dispatch Force. That means one conversation covers the booking, the mode split and what happens the moment the cargo lands: receiving, prep and pick and pack from the same building. If you are weighing air against ocean on a live purchase order, send us the cartons, dimensions, weights and the date you run out, and we will price the honest version of both. See how international freight works with RitePrep.