Ocean Freight is calculated based on the shipping company's shipping list. At present, shipping companies formulate and publish ship price lists, which have different formats and contents, but the basic content is the same.

Firstly, based on the type and nature of the goods, as well as the difficulty of loading and storage, the shipping list of a shipping company is generally divided into several levels. The basic rates charged by shipping companies on the same route vary depending on the level of cargo. Therefore, the level of goods is closely related to the level of rates.

Secondly, the calculation standards for freight are also different. For example, heavy goods are generally charged by weight tons, light goods are charged by size tons, some high-value goods are charged by a certain percentage of the FOB value of the goods, some goods are calculated by weight tons or a mixed method of tons, and the next is ad valorem goods calculated by weight tons or tons, as shown in the following main types of freight tables:

1) The freight is calculated based on the weight of the goods, denoted as W, which is usually the actual gross weight of the goods.

2) The freight should be calculated based on the volume of the goods, denoted as M, which is measured to indicate the size or volume of the goods. In fact, the freight is calculated based on the volume and weight of the goods. The freight volume is converted into weight based on a certain coefficient, namely volumetric weight.

3) Calculate the freight based on one of the higher weight or volume of the goods, expressed as:; W≤M" Among them, W is Weight, which means measurement, referring to W or M, and the freight is calculated based on the larger Weight. How to convert volume and weight first? Firstly, based on a certain conversion factor or formula, the calculated volume weight is compared with the actual weight by calculating the weight according to the volume of the goods, and charged according to the actual weight of the goods.

4) Calculated as a certain percentage of the FOB value of the goods, using AdVal or A.V. It is an abbreviation for AdValorem (ad valorem freight).

5) According to the weight, volume, or value of the goods, sea freight is calculated based on the higher weight, volume, or value of the goods, expressed as:; W/MorAdVal" ， W is the weight, M， Namely measurement, AdVal， The value of the goods.

6) There are also goods collected by per unit or per head, with the former being vehicles and the latter being live animals, etc; For commodities such as grain, ore, coal, etc., due to their large quantity, low price, and easy loading and unloading, shipping companies can reach agreements with shippers separately in order to compete for the source of goods.

According to the freight table, calculating freight is a complex task that requires not only familiarity with the basic content of the transportation list, but also careful work. When calculating freight, in addition to calculating based on route and product grade, the basic freight is also calculated based on the Base Rate, and various additional fees are determined, taking into account the additional fees to be charged.

There are many additional fee items, for example, depending on the product, port, or other reasons, there may be additional fees, but they must also keep up with their changes.

There are generally several types of sea freight surcharges:

（1） Additional fees incurred due to different product characteristics, such as overweight surcharge, extra long surcharge, packaging fee, washing fee, etc.

（2） Additional fees charged due to different ports, such as port congestion surcharge, port selection surcharge, direct shipping surcharge, bypass surcharge, etc.

（3） Temporary increase in surcharges due to other reasons, such as fuel surcharges, currency depreciation surcharges, comprehensive increase surcharges, temporary risk surcharges, peak season surcharges, freezing surcharges, etc.

In fact, the name range of ocean freight surcharges is very wide, far more than the above. It is worth noting that some surcharges, such as port congestion surcharges, account for a large proportion of freight costs, which are 10% lower than the basic freight cost, or even 100% of the basic freight cost, or even more than twice the basic freight cost. Therefore, when calculating freight costs, we must pay attention to the calculation of surcharges to avoid unnecessary losses.