Your sales tax obligations depend on where you’ve established nexus. Nexus is the legal connection between your business and a state that requires you to collect and remit sales tax. For Shopify sellers, this usually comes down to economic nexus based on your sales volume in each state.

Most states adopted economic nexus rules after the 2018 Supreme Court decision in South Dakota v. Wayfair. The common threshold is $100,000 in sales or 200 transactions in a state during the current or previous calendar year. Some states use only the dollar threshold. A few have higher limits like Texas and California at $500,000. You need to track your sales by state and know when you’re approaching these numbers.

Once you exceed a state’s threshold, you have obligations. First, register for a sales tax permit in that state before you start collecting. Collecting sales tax without a permit is illegal in most states. The registration process varies but typically involves filing an application with the state’s department of revenue and waiting for a permit number.

After registration, configure Shopify to collect the correct amount. Shopify has built-in tax calculation tools that handle rates for different jurisdictions. You can also integrate third-party apps like TaxJar or Avalara for more complex situations. The tax rate isn’t just the state rate. Many locations have county and city taxes that layer on top, so automated calculation matters more than you might expect.

Collecting tax is only half the job. You also need to file returns and remit what you’ve collected on schedule. Filing frequency depends on your sales volume in each state. High-volume sellers file monthly. Lower-volume sellers file quarterly or annually. Miss a deadline and you’ll face penalties and interest that add up quickly.

Massachusetts uses the $100,000 threshold. If you’re selling nationwide from the Merrimack Valley or Greater Boston area, you may have nexus in a dozen or more states depending on where your customers live. Each state has its own registration process, rates, filing schedule, and rules about what products are taxable. Clothing is exempt in some states. Digital products are taxable in some but not others. The rules vary widely.

Tracking all of this manually becomes unmanageable fast. Your Shopify dashboard shows where orders are shipping, but you still need to monitor thresholds, register when you cross them, and file returns on time in every state. One missed registration or late filing can trigger notices that take time and money to resolve.

Working with an Andover, MA bookkeeper who understands e-commerce can help you stay on top of registration deadlines and filing requirements before they become problems. Sales tax compliance across multiple states is one of the most complex parts of running a Shopify business, and the penalty for getting it wrong isn’t just fines. Some states audit aggressively and can assess back taxes for years of sales you should have collected but didn’t. Getting systems in place early is always cheaper than cleaning up a mess later.