A freight quote can look simple at first. A rate per kilogram, a rate per container, a total at the bottom. Then the invoice arrives with extra lines, and the final cost is higher than expected. The gap usually comes from how the charge is measured and which add-ons apply.
This guide shows how freight charges are calculated for air and sea cargo, with worked examples you can reuse for your own shipments.
What affects freight charges?
Five factors shape almost every freight quote:
- Mode. Air costs more per kilogram. Sea costs less but takes longer.
- Size and weight. Carriers care about both the space your cargo takes and how much it weighs.
- Route. Distance, port or airport pair and demand on the lane.
- Service level. Express, standard or economy.
- Cargo type. Dangerous, temperature controlled or oversized goods cost more to move.
Delivery terms also matter. They decide whether freight is paid by you or your supplier, and which charges sit on which side. Our guide on choosing between air and ocean freight explains how mode changes both cost and timing.
How air freight charges are calculated
Air freight is priced on chargeable weight. That is the higher of two numbers: actual weight and volumetric weight. Volumetric weight in kilograms equals length times width times height in centimetres, divided by 6,000, a divisor set as an industry standard by IATA.
Worked example 1: dense cargo
A carton measures 60 cm by 50 cm by 40 cm and weighs 28 kg.
- Volumetric weight: 60 x 50 x 40 = 120,000, divided by 6,000 = 20 kg
- Actual weight: 28 kg
- Chargeable weight: 28 kg, because it is higher
Worked example 2: light, bulky cargo
A carton measures 90 cm by 60 cm by 50 cm and weighs 12 kg.
- Volumetric weight: 90 x 60 x 50 = 270,000, divided by 6,000 = 45 kg
- Actual weight: 12 kg
- Chargeable weight: 45 kg
In the second case you pay for 45 kg even though the carton weighs 12 kg. This is why packaging matters in air freight. Tighter cartons and less empty space reduce volumetric weight directly. Some courier services use a different divisor, so confirm which one your carrier applies.
Air freight total
Once you have the chargeable weight, the basic calculation is:
Chargeable weight x rate per kg = base freight
Then add fuel and security surcharges, airport handling, documentation and any customs or delivery charges. Quotes are often airport to airport, so check whether pickup and delivery are included. For urgent cargo, see our air freight service.
How sea freight charges are calculated
Sea freight depends on whether you ship a full container or share one.
FCL: priced per container
You pay a flat rate for a 20 foot or 40 foot container on a given route. Your cost does not change if the box is half full. On top of the base rate, you will see origin and destination terminal charges, documentation and surcharges. Read more in our guide to FCL shipping, its costs and benefits.
LCL: priced per cubic metre or tonne
For shared containers, carriers usually charge on whichever is higher: volume in cubic metres or weight in tonnes. A common rule treats one cubic metre as equal to one tonne.
Worked example 3. A shipment measures 2 m by 1.2 m by 1 m and weighs 800 kg.
- Volume: 2 x 1.2 x 1 = 2.4 cubic metres
- Weight: 0.8 tonnes
- Chargeable unit: 2.4 cubic metres, because volume is higher
If the rate is the same per unit, you pay for 2.4 units. Add CFS handling at both ends and documentation fees. Our post on LCL shipping covers how the shared container process works.
When does FCL beat LCL?
Importers often treat 14 to 15 cubic metres as the point to compare LCL against a full 20 foot container. Ask for both quotes in that range, since the cheaper option can change with the route and season.
Common surcharges and add-on charges
The base rate is rarely the full story. Look for these lines:
| Charge | What it covers |
|---|---|
| Terminal handling charge (THC) | Moving the container between the ship and the yard |
| Bunker adjustment factor (BAF) | Fuel cost changes on sea freight |
| Currency adjustment factor (CAF) | Exchange rate changes |
| Documentation fee | Bill of lading or airway bill processing |
| Peak season surcharge | Higher demand periods |
| Fuel and security surcharges | Applied by airlines |
| Delivery order fee | Release of cargo at the destination |
| Inland haulage | Trucking to or from the port |
| Demurrage and detention | Delays beyond free time |
Terminal handling and documentation fees vary by carrier, port and container size, so compare them line by line. Surcharges such as BAF and CAF are common on ocean freight, as shown in published carrier local charge guides.
Charges that sit outside freight
Freight is only part of your landed cost. Remember to add:
- Marine or air cargo insurance
- Customs duty and IGST on imports
- Customs broker and port charges
- Warehousing and trucking after clearance
Our guide to customs clearance charges in India breaks down the clearance side. If cargo needs to wait before delivery, warehousing adds storage and handling costs.
A simple formula to estimate total cost
- Work out chargeable weight (air) or chargeable cubic metres or container count (sea).
- Multiply by the quoted rate to get base freight.
- Add origin charges, such as pickup, documentation and export clearance.
- Add surcharges.
- Add destination charges, such as terminal handling, delivery order and clearance.
- Add insurance, duty and taxes.
- Add trucking and delivery to your final address.
Do this for every quote you receive, so you compare the same total rather than headline rates.
Ways to lower your freight cost
- Pack tight. Remove void fill and oversize cartons to cut volumetric weight on air shipments.
- Pick the right mode. Move non-urgent goods by sea and keep air for time-sensitive stock.
- Consolidate orders. Combine small orders into one shipment where lead times allow.
- Compare FCL and LCL. Ask for both quotes when volume is near the break-even range.
- Book early. Space is cheaper and easier to find outside peak weeks.
- Check free days. Negotiate more time to cut storage and container delay costs.
- Share documents early. Faster clearance means fewer storage days.
- Review the full quote. Look at surcharges, not just the base rate.
How IWCC helps you plan freight costs
Interworld Cargo Care works with more than 50 shipping lines to price air and sea freight on over 1,000 routes. Our sea freight team compares FCL and LCL options, and our door to door service quotes pickup, freight, clearance and delivery together. You receive an itemised estimate before you commit. If you are new to trade, our step by step guide to the import-export process in India shows where freight fits in.
Get an itemised freight quote
Send us your cargo dimensions, weight and route, and we will calculate the chargeable weight or volume and the total landed cost. Request a free quote or call 098110 59654.