Air freight is often 4-6x more expensive per kilogram than ocean freight, which leads many shippers to rule it out by default. But the per-kilogram comparison misses the parts of the equation that actually determine total cost: inventory carrying cost, warehousing, and the cost of a stockout.
The Hidden Cost of Slow Transit
Ocean freight from Asia to the US typically takes 20-35 days door to door, versus 3-7 days by air. Every day of transit is a day your capital is tied up in inventory that isn't generating revenue — and for high-value or fast-moving goods, that carrying cost adds up quickly.
When Air Freight Actually Wins
- High value-to-weight products (electronics, pharmaceuticals) where freight cost is a small percentage of product value
- Time-sensitive launches or promotional windows where a stockout costs more than the freight premium
- Low inventory buffer situations where a delayed ocean shipment risks a full production stoppage
- Smaller shipment volumes where ocean's cost advantage from scale doesn't materialize anyway
A Simple Way to Run the Math
Compare the freight cost difference against the carrying cost saved by the faster transit (using your cost of capital and average inventory value), plus the estimated cost of a potential stockout weighted by its likelihood. For high-value, fast-moving SKUs, air freight frequently comes out ahead once the full picture is included — not just the freight invoice.
Ocean freight optimizes for cost per kilogram. Air freight optimizes for cost per day. The right choice depends on which one is actually scarce in your business.