This question is not asking "what should my rate be?"
I would like to some help understanding how to choose a rate. What are some successful methods that others have used in deciding what to charge in terms of time-based work?
My business is early on in the startup phase, and the first method that I used for consultancy-based work is by deciding on an annual salary I'd be happy with - let's say £20,000 to keep it a round number - and dividing this by the number of days per year (let's say 250 working days days, then multiplying by the number of days work required to complete it, and then adding 20% - giving a rate of £100 per day. I thought the 20% was a clever way of getting more money from what I put in, but in reality I don't think I'm asking for enough.
The reason I've found myself feeling out-of-pocket is because, as I'm sure most of you on this website know all too well, there is a lot of time spent when setting up a business on things that don't directly earn you money. That, and the fact that it is very difficult to maintain solid work all the time means that the 20% figure becomes very insignificant.
Luckily, most jobs that I have done are one-off pieces of work, so I'm not going to have to negotiate with existing clients on a price increase, but I have realised that one-off jobs can have a much higher asking price... but how high is reasonable, and how can I calculate this?
In case this helps your answer, the business is software and networking, mainly consultation & bespoke software development.