Selling on Shopify, WooCommerce, and BigCommerce: Sales Tax Setup Guide

Your ecommerce platform calculates the tax your customers see at checkout, but it only knows what you tell it. If tax collection is switched on in the wrong states, product categories are left blank, or shipping is set up incorrectly, the platform will charge the wrong amount on every order. This ecommerce platform sales tax setup guide walks through Shopify, WooCommerce and BigCommerce, what each tool does and does not do, and a setup checklist that applies to all three.

Before You Touch Platform Settings

1. Determine where you have nexus using physical presence and economic nexus thresholds.
2. Register in those states before collecting. See multi-state sales tax registration.
3. List your products and their tax treatment, such as clothing, groceries, digital goods or software. Our guides on clothing, groceries and digital goods and software help.
4. Separate marketplace channels. Orders on Amazon or Etsy are taxed by the marketplace, not your store. See marketplace vs direct sales tax liability.

Platform Comparison

Platform features and fees change. Confirm current details in each platform’s help center before you commit.

Shopify Setup

1. Enter your business address and confirm your store currency.
2. Add each state where you are registered and turn on collection, entering your state tax ID.
3. Assign product categories so Shopify Tax can apply exemptions and reduced rates.
4. Review shipping taxability for each state; Shopify follows state rules when collection is active.
5. Mark tax-exempt B2B customers and store their certificates.
6. Track the $100,000 lifetime sales point, after which the calculation fee applies to orders in states where collection is active.

WooCommerce Setup

1. Enter a complete store address under WooCommerce > Settings > General; WooCommerce Tax uses it as your primary tax location.
2. Install WooCommerce Tax and connect your site to WordPress.com.
3. Select Enable tax rates and calculations, then set Automated taxes on the Tax tab.
4. Review rates for each state where you are registered. WooCommerce notes that the extension does not determine where you have tax obligations, so confirm that collection covers every state you need.
5. Set product tax classes for exempt or reduced-rate items.
6. Check shipping taxability. WooCommerce Tax applies tax to shipping by default for Florida-based stores shipping to Florida; review other states with your advisor.
7. For multistate sellers with many product types, consider a third-party tax plugin that also files returns.

BigCommerce Setup

1. Go to Settings > Tax and click Add tax service.
2. Install Avalara, Vertex, TaxJar or TaxCloud and enter your provider account details. You need Store Owner rights or app install and launch permissions.
3. Configure nexus states and local jurisdictions in the provider’s dashboard.
4. Map product tax codes and enable exemption certificate handling for B2B customers.
5. Test sample orders using the provider’s calculator.

Test Before You Go Live

Place test orders to addresses in several states and compare the tax with an independent source.

For shipping rules, see shipping and handling by state and sales tax on freight and shipping charges. Check city rates on the Dallas, Richmond and Phoenix pages.

Ongoing Maintenance Checklist

• Monthly: reconcile tax collected by state with your platform reports and returns.
• Quarterly: review sales by state against nexus thresholds and activate new states after registering.
• When adding products: assign tax categories before publishing.
• When laws change: review settings, for example after Washington’s October 2025 expansion to new services.
• When errors appear: correct settings and amend affected returns.

Conclusion

Every ecommerce platform sales tax setup guide starts in the same place: decide where you must collect, register, and only then turn on collection. Shopify, WooCommerce and BigCommerce all calculate tax well when products, addresses and states are configured correctly, but none of them decides your obligations or guarantees filings by default. Test orders, reconcile monthly, and consider automation such as a certified service provider. Look up rates on our state sales tax pages, check totals with the Add/Remove Sales Tax Calculator, and start from the Tax Rate Center homepage.

Frequently Asked Questions