"Fixed price" refers to the price of each weight range instead of the unit price; it is a converted fixed price according to the weight. The algorithm is as follows:

**The gross freight=The fixed price of some weight range+operation fee.**

**一. The limitation of each cell:**

- Weight limit: 0.001-1000;
- Operation fee: 0-1000;
- Delivery time: 1-100;
- Range-weight: 0.001-1000;
- Range-price: 0.0001-1000;

**Two. The linkage limitations among cells:**

- Weight limit: All the weights must be less than the weight limit;
- Delivery time: The maximum delivery time must be less than the minimum delivery time;
- Range-weight: The left range weight must be less than the right range weight;
- Range-the right range weight: cannot be empty;
- Range-the right range weight(the last one): must be equal to the weight limit;
- 20 ranges can be added at most;

**Three. Examples:**

Take the above screenshot as an example, if a user enters 2.5KG, it belongs to the range 2-5, then the gross freight should be 12 (the fixed price corresponding to the interval) +0 (operation fee) =12.