This is in accordance with the US sales tax system. 

In the United States, most states have a sales tax system and vendors should collect sales taxes when the sales volume exceeds a certain amount. Following this regulation, we are required to collect sales taxes in certain US states, which will be transferred to your state government. If you are seeing US sales taxes collected on our website for the first time, it is because our sales volume recently exceeded the minimum threshold in the state you are ordering from.

Sales tax rates vary from state to state, so please click here for more detailed information.