How Automatic Tax Calculation works

Automatic Tax Calculation uses a rule-based model that combines your tax registrations, product tax categories, customer location, and configuration to determine the correct tax treatment for each billing transaction.

The tax compliance lifecycle

To stay compliant with indirect tax (sales tax, VAT, and GST), every business must do four things repeatedly:

1. Understand obligations: Know which locations require you to collect tax, for example, where you have nexus or cross economic nexus thresholds.
2. Register: Register with tax authorities in those locations before you start collecting tax.
3. Calculate and collect: Apply the correct tax on each invoice, subscription, or checkout transaction based on the rules in that location.
4. Report, file, and remit: Periodically report what you collected and pay it to the tax authorities.

Automatic Tax Calculation uses the configuration you provide in steps 1 and 2 to support step 3, and provides an associated tax report to support step 4.

The four pillars of automatic tax

Billing only applies automatic tax to a line item when all four of the following conditions are met.

1. Automation is enabled

• Enable global tax automation is ON in Billing Settings → Tax.
• Automatic tax is enabled for the specific invoice, subscription, or Hosted Billing Checkout.

2. You have a tax registration in the customer's region

• You have added a tax registration for the country, state, or province relevant to the customer.
• The registration is active for the date of the transaction (not expired and not scheduled for a future date).

3. The product has a tax category

• The Billing product used on the line item has a tax category assigned, such as SaaS – Business, Digital Audio – Subscription, or Digital Books – Permanent.

4. The customer has a valid billing address

• The customer's billing address is present and usable. Most regions require only the customer's country to accurately calculate a tax rate.
• For some countries such as the US and Canada, a valid postal or ZIP code is required to determine the correct local rate. If a nine-digit ZIP code is not provided, Billing defaults to the five-digit code to determine the most appropriate rate.

If any pillar is missing, Billing cannot reliably determine the proper tax treatment. It explains what is missing and offers two remedies:

• Fix data: Assign a category, add an address, or add a registration.
• Switch to manual tax: Enter the tax rate yourself for that invoice, subscription, or Hosted Billing Checkout.

For more information on resolving missing-data errors, see Use Automatic Tax Calculation.

Tax inclusion: inclusive versus exclusive pricing

Billing supports both tax inclusive and tax exclusive pricing.

• Tax inclusive: The catalog price you enter already includes tax. Billing backs out the tax from the total to compute the net amount (before tax) and the tax amount. This is common in consumer-facing contexts in AU and NZ, where prices are typically advertised as tax included.
• Tax exclusive: The catalog price is before tax. Billing adds tax on top of the price. This is common in B2B or US and CA contexts where tax is usually shown as a separate line at checkout or on the invoice total.

You choose the default behavior in Billing Settings → Tax → Tax inclusion:

• Tax inclusive: The price includes tax.
• Tax exclusive: Tax is added on top of the price.

Tax inclusion examples

Example 1 – Tax inclusive

Example 2 – Tax exclusive

Automatic versus manual tax

Billing uses a "mandated autonomy" approach:

• Automatic tax is the default where possible once enabled. If your data is complete, Billing calculates tax automatically for each line item.
• Manual tax is always available. You can disable automatic tax for a specific invoice, subscription, or Hosted Billing Checkout and specify the tax rate yourself as a percentage.

In tax reports, Billing clearly distinguishes automatic entries (system-calculated) from manual entries (user overrides). This distinction supports audits and internal review. For more information, see Tax reports and exports.

Examples

Example: B2B SaaS subscription in the EU

You are a UK-based SaaS provider registered for VAT in several EU member states. Your product costs EUR 50/month, tax exclusive. You have a VAT registration in France, a product tax category mapped to SaaS – Business, and a French customer with a full billing address.

Depending on your configuration and applicable rules:

• B2C sale (no VAT ID): Billing identifies the customer as a consumer in France and applies the standard French VAT rate for the SaaS category. The invoice shows net price, VAT, and gross total.
• B2B sale with VAT ID: If configured and supported, Billing may treat the transaction as reverse charge, where the buyer accounts for VAT and no VAT is collected on the invoice, but the treatment is still recorded for reporting.

Example: US state sales tax on one-off invoices

You are a US-based company registered in California only. You sell a digital service for USD 200, tax exclusive. You issue:

• Invoice A to a customer in Los Angeles, CA.
• Invoice B to a customer in Seattle, WA.

You have a registration in California but not in Washington, and the product is correctly categorized.

Billing does the following:

• For Invoice A: Uses the customer's ZIP code to determine the applicable California state and local rate, then calculates and applies sales tax.
• For Invoice B: Sees that you do not have a registration in Washington and applies 0% tax.

You remain responsible for monitoring when economic nexus thresholds are crossed and for registering in new states when required.