# Tabs Integration (via QuickBooks)
Tabs integrates with **QuickBooks Online** via Sphere to handle tax calculation. When you process an invoice in Tabs, a corresponding invoice is created in QuickBooks. Sphere then computes the applicable taxes and injects them directly into the QuickBooks invoice. Tabs continuously monitors the QuickBooks invoice for updates and automatically reflects the calculated taxes once they appear.
The primary integration is between **Sphere and QuickBooks**, with Tabs acting as the interface to trigger and display the tax calculations.
### **Prerequisite:** Connect QuickBooks with Sphere
Follow this guide to configure your QuickBooks integration with Sphere. [quickbooks-integration](https://docs.getsphere.com/features/integrations/prebuilt-connectors/quickbooks-integration "mention")
### **Tax Calculation Flow in Tabs**
1. To calculate tax for a specific invoice in Tabs, go to the **Invoices** tab and select the desired invoice. Then, click **Submit** in the top-right corner to start the tax calculation for that invoice.
2. This action will create a new invoice in QuickBooks and initiate tax computation asynchronously. Sphere will handle the tax computation and inject the calculated taxes directly into the QuickBooks invoice. Once completed, the taxes will automatically appear on the corresponding QuickBooks Online invoice after a brief delay.
3. Tabs will continuously poll the QuickBooks invoice for updates and will automatically pick up the taxes as soon as they appear. However, due to the asynchronous nature of the tax calculation process, there may be a slight delay before Tabs detects and applies the taxes.
