The main factor to the calculation of agent shipping prices is the weight.
Logically, you multiply the price per weight unit (usually 500g or 1kg) by the amount of weight units. This information can be found on the agent's shipping calculator.
You will also find the price for the initial weight. This makes everything more complicated, because this price includes the overhead, because naturally smaller parcels are more expensive per kilogram than bigger parcels.
This leads you to the following equasion:
shipping price = [initial weight price] + ([weight-initial weight unit] / [continued weight unit] * [continued weight price])
If that's too complicated, let us do it for you and use our shipping calculator.
added: 6/26/2023