Most freelancers price as if a 40-hour week is 40 hours they can sell.

It is not.

Admin, proposals, revisions you did not quote, context-switching, invoicing, and the hours that disappear into Slack eat the rest. For a lot of people the real number is closer to 22 billable hours.

That is why a rate that "looks fine" on a calculator still leaves you short at the end of the month. The rate was never the only problem. The hours you thought you were selling were.

A simple check: take last month. Add up the hours you actually invoiced. Divide by the hours you were at the desk. That ratio is the one your rate has to survive.

If you do not know that number, you do not have a rate. You have a guess.