You should collect 5% of total sales for GST.
We recommend regularly transferring the GST collected (or a portion of it) to a savings account so you don’t spend it like it's your money. Here are the two ways to calculate how much GST you need to remit to the government:
Net GST
This is the default and most common method for calculating how much GST your business owes. When you purchase goods and services for your business, you’ll also be paying GST on those bills. To calculate how much you need to remit, add up all the GST you collected during the period, and subtract all the GST you paid during the period, to get your net GST payable. The GST you pay on goods and services are called Input Tax Credits, or ITCs.
Quick Method
Certain businesses that qualify can elect to use the Quick Method. With this method, you simply take 3.6% of Sales (including GST) and remit that to the government. There are several rules and variations, but most contractors, consultants and freelancers would qualify for the Quick Method at 3.6%. You would still charge 5% GST on Sales. This method is great for service-based businesses who don’t purchase a lot of goods and therefore don’t have a lot of ITCs. They can end up actually making a bit of margin using the Quick Method.