The basic formula is simple. Take your taxable sales for the filing period and multiply by your sales tax rate. In most of the Richmond area, the combined Virginia state and local rate is 5.3%. So if you had $15,000 in taxable sales during the month, you owe $795 in sales tax.

The harder part is making sure you’ve identified taxable sales correctly. Not everything you sell is taxable in Virginia. Most tangible goods are, but many services aren’t. Sales to tax-exempt organizations with valid exemption certificates don’t count. Neither do resale transactions where the buyer provides a resale certificate. If you sell food for home consumption, that’s taxed at a lower rate of 2.5% rather than the full 5.3%.

If you’re collecting sales tax at the register or on invoices, which you should be, the tax you collected should closely match the tax you owe. They’re not always identical because of rounding on individual transactions, but they should be close. If there’s a significant difference, something is wrong. Either you’re not collecting on all taxable sales, or you’re collecting on things that aren’t taxable.

To pull the numbers, run a sales report for the filing period in your accounting software. Look for the total sales figure, then identify any non-taxable amounts. Your sales tax setup in QuickBooks or whatever system you use should be separating taxable from non-taxable automatically if it’s configured correctly.

Compare your calculated tax liability against the sales tax liability account in your books. That account tracks what you’ve collected from customers. When you remit payment to Virginia, you’re paying down that liability. If the account balance doesn’t match what you’re about to pay, investigate before filing.

Virginia requires most businesses to file monthly if they collect more than a certain threshold. Smaller businesses may file quarterly. The return asks for gross sales, exempt sales, and taxable sales, then calculates the tax due. Working with a Richmond bookkeeper can help make sure your books are organized so these numbers are easy to pull each period instead of a last-minute scramble.

The most common mistakes are including exempt sales in the taxable total, forgetting to account for different rates on different product types, or not reconciling collected tax against calculated tax. Catch those before filing and the calculation itself is just multiplication.