Mode comparison

Air, sea, rail comparison

Compare sea, air, and rail (China-Europe) on total cost including inventory carrying cost. The cheapest freight rate is rarely the cheapest total once you add the inventory tied up in transit. The math runs in your browser.

Last updated 2026-05-09. Math runs in your browser, no data leaves your computer.

General guidance only, not legal or professional engineering advice. Verify against the cited primary sources (IMDG, REACH, ChAFTA, RCEP, Customs Tariff Act, supplier SDS, etc.) before committing to a shipment, declaration, or contract. Sourzi assumes no liability for outcomes based on these calculators.

Default rates are starting points; replace with your actual forwarder quotes. The tool computes total cost = freight cost + (cargo value times annual carrying cost rate / 365 times transit days).

Cargo

Sea

Air

Rail (Asia-Europe block train)

Total cost is freight plus inventory tied up in transit

Freight rate alone is the wrong number for mode choice. A 2,400 USD sea freight quote and a 5,500 USD rail freight quote look like sea wins by 3,100 USD; once you add the inventory carrying cost (the cargo capital tied up while in transit), the gap narrows. At 35,500 USD cargo value, 20 percent annual carrying cost, 28-day sea transit: carrying cost is 35,500 * 0.2 * 28 / 365 = 545 USD. Sea total: 2,945 USD. Rail at 18 days: carrying cost 350 USD. Rail total: 5,850 USD. Sea still wins, but by 2,905 not 3,100. For higher-value cargo the gap narrows further.

At the breakpoint where rail beats sea, cargo value is high enough that the 10-day faster transit pays for the rail freight premium. For 25,000 kg of caustic soda at 1.42 USD per kg = 35,500 USD value, rail does not beat sea. For 25,000 kg of catalyst at 12 USD per kg = 300,000 USD value, the calculation flips: 28-day sea carrying cost is 4,602 USD, 18-day rail carrying cost is 2,959 USD. Sea total 7,002 USD, rail total 8,459 USD. Still sea wins. For 25,000 kg of fine pharma intermediate at 50 USD per kg = 1,250,000 USD value, sea carrying cost is 19,178 USD, rail 12,328 USD. Sea total 21,578, rail total 17,828. Rail wins by 3,750 USD on this cargo profile.

Air wins when schedule is binding rather than cost-optimal. A buyer customer running JIT inventory on a fine chemical input cannot afford a 28-day sea or even an 18-day rail; the production line stops. Air at 6 days transit costs 5 to 8 times sea per kilogram, but the cost of the production line stopping for 22 days dwarfs the freight premium. The mode-choice question on an urgent shipment is "what does the production line cost per day idle" not "what does the freight cost".

Mode choice should be made on total cost including carrying cost, with schedule as a hard constraint when binding. The matrix exposes both numbers; the buyer makes the call with full information.

Worked example. The $50/kg fine chemical

The booking. A US distributor needs 5,000 kg of a fine chemical intermediate at 65 USD per kg, total cargo value 325,000 USD. Forwarder quotes: sea LCL 1,800 USD all-in 28 days, air 7.50 USD/kg 5 days, rail not applicable on this Asia-US lane. Carrying cost rate 25% (high-value cargo, short shelf life).

The numbers. Sea freight 1,800 USD; sea carrying cost 325,000 * 0.25 * 28 / 365 = 6,234 USD; sea total 8,034 USD. Air freight 5,000 * 7.50 = 37,500 USD; air carrying cost 325,000 * 0.25 * 5 / 365 = 1,113 USD; air total 38,613 USD. Sea is 4.8 times cheaper than air on total cost. Looks like sea wins. But the buyer customer JIT line burns 12,000 USD per day idle. If sea transit slips by 7 days (one missed sailing), the cost of the slip is 84,000 USD in production losses, dwarfing both freight totals.

The decision. For a single shipment with no schedule pressure, sea wins. For a shipment that has to land by a specific date and the buyer cannot absorb a 7-day slip, air is the right call despite costing 30,500 USD more. The matrix surfaces the numbers; the buyer customer schedule constraint determines which one applies.

Frequently asked

How does this tool compare modes?

Three side-by-side: sea LCL or FCL, air, rail (China-Europe Block Train). Enter the per-mode rate quote you got from your forwarder, the transit days, the destination handling cost; the tool returns total cost per shipment, cost per kilogram, and per-day inventory carrying cost. Output: a clear pick when one mode dominates, a trade-off lens when they cross.

When does rail beat sea?

On Asia-Europe lanes specifically. The China-Europe rail block train (15 to 22 days) is faster than sea (28 to 40 days via Suez or Cape) and cheaper than air. Sweet spot: cargo with a 14-to-21-day inventory tolerance and value above 5 USD per kilogram. For high-value chemicals (catalysts, fine intermediates), rail saves enough working capital to outweigh the per-kilogram premium over sea.

When does air beat sea or rail?

When schedule is binding. Air on Asia-US is 5 to 7 days door-to-door; sea is 21 to 35; rail does not run on this lane. For samples, urgent batch replacements, or cargo above 20 to 30 USD per kilogram, the air premium pays back as schedule certainty.

What inventory carrying cost should I use?

Total annual cost of holding inventory divided by 365 then multiplied by transit days. Annual cost typically 15 to 30 percent of inventory value (capital cost 6 to 10 percent, warehouse 4 to 8, insurance 1 to 2, obsolescence 4 to 10). For chemicals with shelf life under 2 years, use the upper end.

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