Sea vs Air Freight from China: How to Choose
Choosing between sea and air freight from China: volumetric weight, the 15 m³ FCL break-even and the cost of capital tied up in transit.
Sea freight is cheaper per unit and air freight is faster; the right decision depends not on the freight rate but on the total cost, which includes the capital tied up during transit. A product with a high value per kilo and a tight margin is usually cheaper to ship by air even when the air rate is five times the sea rate. A bulky, low-value product can almost never pay for air.
This guide explains how to run the numbers.
First: how each one is charged
Consolidated sea freight (LCL) is charged by cubic metre. There is a minimum per shipment — typically a minimum equivalent to 1 m³ even if you ship less — so consolidating with other orders is what makes the number work. That is the whole logic behind cargo consolidation.
Full container load (FCL) sea freight is charged per container. A 20-foot container holds around 28 usable m³ and a 40-foot container around 58–60 m³. From about 15 m³, FCL is usually cheaper than LCL: you book a 20-foot container and the cost per cubic metre falls.
Air freight is charged by kilo, and here is the trap: you are billed on the greater of the actual weight and the volumetric weight, which is calculated by dividing the volume in cubic centimetres by a factor that is usually 6,000 for general air cargo.
The practical formula:
Volumetric weight (kg) = (length × width × height in cm) ÷ 6,000
A light, bulky product — a rug, a pillow, a large box full of air — is charged for the space it occupies, not for what it weighs. That is why reducing packaging lowers the bill without touching the product.
The number almost nobody calculates: value per kilo
The right question is not “how much does the freight cost?” but “what percentage of the product’s value is the freight?”.
| Category | Approximate value per kg | Sensible route |
|---|---|---|
| High-value consumer electronics | High | Air |
| Phone accessories, small | Medium-high | Air or sea, depending on volume |
| Textiles and apparel | Low-medium | Sea |
| Housewares and plastics | Low | Sea |
| Furniture and bulky items | Very low per m³ | Sea, almost always FCL |
Working rule: if air freight exceeds 15–20% of the value of the goods, the product probably cannot carry the air cost. If sea freight takes so long that it leaves you out of stock in peak season, the saving is worth nothing.
The cost of capital tied up in transit
This is the part that gets forgotten. While the goods are in transit, your money is tied up and your product is not selling.
An example with round numbers:
- Goods: USD 20,000
- Sea transit: 35 days · Air transit: 10 days
- Difference: 25 days of lost sales
- If your product turns and generates 3% margin per week on the capital, those 25 days are roughly USD 1,500 of margin not generated
- Sea freight: USD 1,800 · Air freight: USD 6,500
- Freight difference: USD 4,700
In that scenario sea freight still wins. But if the product carries a higher weekly margin — fast-moving electronics, seasonal goods, a launch — the gap closes quickly. And in peak season, running out of stock does not cost you margin: it costs you marketplace ranking, which takes months to recover. That is the real argument for keeping MercadoLibre Full inventory supplied.
When air freight almost always wins
- Product launch. You need to validate demand before committing to a container.
- Urgent restock. What was selling has run out and sea freight arrives too late.
- High-value, low-volume product. Electronics, cosmetics, jewellery, instruments.
- A season with a fixed date. Buen Fin, Christmas, Hot Sale. Arriving late is arriving with nothing.
- Samples and trial orders. The freight cost is irrelevant next to the value of learning, and a China sourcing agent can group samples from several suppliers into one shipment.
When sea freight almost always wins
- A bulky product with low value per m³. Furniture, plastics, housewares, textiles.
- Large, predictable orders. If you can plan 60 days ahead, sea freight is free compared with air.
- More than 15 m³. That is where FCL changes the economics completely.
- Safety stock for several months. If you are going to store it anyway, there is no rush.
The calculation worth running every time
Before choosing, work out these five numbers:
- Total volume in m³ for the whole order, with the real packaging.
- Actual weight and volumetric weight (volume in cm³ ÷ 6,000).
- Sea and air quotations for that exact volume and that exact weight.
- Expected weekly margin on the capital tied up.
- Days of difference between the two routes, door to door.
With those five you decide in two minutes, and the answer is almost never “the cheapest one”.
A very common mistake
Comparing the freight price per kilo between sea and air. They are not comparable: sea freight is quoted by volume and air freight by volumetric weight. To compare them properly you have to calculate the total cost of the whole shipment by each route, including customs clearance, local delivery and transit days.
That is exactly what we do when we quote: you get both routes with the total cost delivered to your warehouse and the real lead time of each, so the decision is made on numbers rather than on an isolated freight rate.