In a fixed-price project, the income is agreed before you know all the hours you will spend. Include meetings, revisions and delivery as well as the main work.
An example with numbers
You quote $1,800 expecting 30 hours. The implied rate is $60/h. If revisions push it to 40 hours, it falls to $45/h. Both figures are before expenses and taxes.
Try it with your numbers
Use the calculated rate and compare two estimates of project hours. Decide which revisions are included in the price and when it would make sense to quote extra work.
Example figures for learning purposes. They are not a recommendation and do not replace professional advice.