The rule of thumb I was told is 1000 billed hours per year. If you want to earn £40k, and are billing by the hour, charge £40 per hour.
That gives you the room to be flexible.
The original article adds extra in as they have a different structure, but they start with $75k and year and end up with $85 an hour. Which seems to me to be close enough.
I used it when I started by company. I think it was good advice.
One thousand billable hours per year seems reasonable, but if you want to earn equivalently to someone who's on a £40k salary you should aim for substantially higher than £40k of revenue.
That gives you the room to be flexible.
The original article adds extra in as they have a different structure, but they start with $75k and year and end up with $85 an hour. Which seems to me to be close enough.
I used it when I started by company. I think it was good advice.