The cheapest freight mode is not always the cheapest business decision, and the fastest mode is not always worth its premium. A useful comparison keeps the cost assumptions and time assumptions separate.
Build the air side
Start with chargeable weight, not only actual weight. Multiply the chargeable kilograms by the quoted rate and add the fixed components you know.
Build the ocean side
For LCL, compare shipment CBM with metric tonnes and apply the quote minimums. Add local and fixed charges so the scenario is not based on the ocean rate alone.
Compare the transit difference
The Air vs Ocean Freight Calculator shows the modeled cost difference and, when air is faster but more expensive, the extra freight spend per day saved.
What the calculator intentionally leaves out
Inventory carrying cost, stockout risk, customs variability, consolidation schedules, reliability and the value of getting product to market sooner can dominate the final decision. Add those considerations outside the freight arithmetic instead of hiding them inside an unexplained score.