No sales tax on the invoice?
You may occasionally make a retail purchase where the invoice doesn’t include retail sales tax. Washington sellers and some out-of-state sellers have a responsibility to collect Washington retail sales tax. However, if sales tax was not collected, the buyer has the responsibility to pay use tax in place of sales tax.
Invoices without sales tax
If you receive an invoice on a retail purchase that does not include sales tax, ask the vendor to issue a new invoice that itemizes the amount of sales tax due. Doing so ensures that both you and the seller understand the amount is for retail sales tax.
If you cannot contact the vendor or they will not issue a corrected invoice, you can pay the tax directly on your Excise Tax Return or by using a Consumer Use Tax Return (if you are not a registered business). Goods used in this state are subject to either sales or use tax, but not both. The use tax compensates when sales tax has not been paid. For record keeping purposes, you should make a note on the invoice to show use tax has been paid.
Do not add the sales tax onto the bill yourself
Unless the seller’s invoice itemizes retail sales tax, there is no way to prove the tax was properly remitted to the department. Washington law requires that customer sales slips, contracts, invoices, or other sales documents separately state the amount of retail sales tax due.
Note: Washington sellers are allowed to advertise sales tax is included in the price of their goods. For the requirements of advertising sales tax included, please see RCW 82.08.055.