Hi andrea-natarelli,
It's important you're able to calculate sales tax from the total revenue on a monthly basis. I'd be glad to steer you in the right direction so you can focus on your business.
QuickBooks is designed to help automate most of the manual tasks involved with the accounting side of your business. While there isn't a sales tax calculator built into QuickBooks yet, I encourage you to check out this tax calculator from the CRA website using the link here. For questions related to calculating the sales tax, I recommend reaching out to an accounting professional for expert advice. Doing this helps prevent any discrepancies in your books. If you're not in contact with an accounting professional, I suggest searching for one on our site using this link here.
Give this a try and if you have questions, I recommend contacting our support team using this link. Otherwise, feel free to leave a comment below. I'll be on standby.