Why Do Container Freight Rates Fluctuate So Much?

Container freight is the most volatile line in your logistics budget. The price for the same container type on the same lane can double or halve within a few months. This article explains why container freight rates fluctuate, what the surcharges on your invoice actually mean and which indices you can use to follow the market.

The basic balance behind container freight rates: supply and demand

At its core, a freight rate reflects the balance between space on ships (supply) and cargo looking for that space (demand).

• Demand: Consumption, production, inventory strategies and trade volumes. When European retailers want to build stock, for example, demand on Asia–Europe rises.
• Supply: The fleet capacity in the market, the number of sailings and how much of that capacity is actually usable.

Capacity is hard to add in the short term; a new ship takes years from order to delivery. If demand jumps suddenly, rates rise quickly. Conversely, when a wave of newbuilds joins the fleet at the same time, overcapacity builds up and rates tend to fall.

Effective capacity: routing matters as much as ship numbers

The number of ships alone is not the full picture. What counts is “effective capacity”, meaning how often those ships can serve a given trade.

The Red Sea crisis is the clearest example. When carriers started sailing around the Cape of Good Hope, they needed more ships to keep the same weekly frequency. The fleet did not shrink, but effective capacity did, and rates rose. As services return to Suez, the reverse happens: ships are freed up and effective capacity grows.

Carriers use a few main tools to manage capacity:

• Blank sailings: Cancelling a scheduled sailing, often used to support rates when demand is weak.
• Slow steaming: Sailing more slowly to save fuel, which also reduces effective capacity.
• Merging or splitting services: Alliances reshuffling their networks.

Seasonality: why some times of year cost more

The container market has clear seasonal cycles:

• Peak season: Usually from mid-summer into autumn, when goods ship for year-end sales in Europe and the US.
• Chinese New Year: Falling in January or February, it triggers a rush before the holiday as factories try to finish orders, followed by a slowdown in production and loadings during the break.
• Golden Week: During this early-October holiday in China, demand usually softens.

Knowing these cycles helps you plan cargo outside peak periods where you can.

Fuel, regulation and crises

Other important drivers include:

• Fuel prices: Bunker fuel is one of a carrier’s largest costs. Changes are usually passed on through the BAF (bunker adjustment factor).
• Environmental regulation: Since the EU Emissions Trading System (ETS) was extended to shipping, many carriers apply a separate surcharge on European trades.
• Geopolitical crises and disruptions: Canal closures, port strikes, pandemics and regional conflicts can tighten capacity overnight.
• Port congestion: Ships waiting at port also reduce effective capacity.

The abbreviations on your invoice: GRI, PSS and more

Quotes usually consist of a base rate plus a series of surcharges. The ones you will see most often:

• GRI (General Rate Increase): A general increase announced by the carrier from a set date. Not every announced GRI sticks; if demand is weak it may be applied only in part or withdrawn.
• PSS (Peak Season Surcharge): A surcharge applied during peak season.
• BAF (Bunker Adjustment Factor): The fuel surcharge.
• THC (Terminal Handling Charge): The fee for handling the container at the terminal.

You can find the full list in our logistics glossary. When comparing quotes, always check what is included; a low base rate can end up more expensive once surcharges are added.

Freight indices: the Drewry WCI and SCFI

Weekly indices help you read the direction of the market:

• Drewry World Container Index (WCI): Published weekly by London-based Drewry, it tracks spot rates for 40ft containers on major East–West lanes.
• SCFI (Shanghai Containerized Freight Index): Published by the Shanghai Shipping Exchange, it tracks spot rates on routes out of Shanghai.

A simple example shows the scale of the swings: the Drewry WCI composite stood at around USD 2,424 per 40ft container on 7 August 2025, and at around USD 4,468 on 24 September 2026.

Indices show the general direction of the spot market; the price for your lane and your cargo may differ. Use an index as a compass and get a current quote for the actual price.

What you can do about volatility

1. Plan early. Do not leave bookings until the last minute before peak season or Chinese New Year.
2. Check quote validity. In volatile markets quotes are short-lived, so align your approval process accordingly.
3. Optimise how you ship. The choice between FCL and LCL directly affects cost. See our article on FCL or LCL for details.
4. Get expert support for regular volumes. If your annual volume is predictable, we can review the balance between contract and spot rates together as part of our logistics consulting service.

Frequently asked questions

What is the difference between spot and contract rates?

A spot rate is that week’s market price. A contract rate is agreed in advance for a set period and volume. Spot is more flexible but volatile; contracts offer predictability.

Does every announced GRI end up in the price?

No. A GRI is the carrier’s target. If demand is strong it largely sticks; if demand is weak it may be applied only partly or not at all.

Why is my quote different from the index rate?

Indices show average spot rates on specific lanes. Your quote also reflects the ports of loading and discharge, cargo type, surcharges and local charges.

When will rates go down?

No one can give a firm date. In general, overcapacity, weak demand and off-peak periods push rates down, while crises and peak season push them up.

At Medius we follow the market for your ocean freight shipments and present quotes transparently, line by line. For a current rate, fill in our quote form.