Many people struggle with this question. Some just try to make as much as a full-time employee makes (and ignore that they won't be able to bill as many days). Others follow tips on startup related websites that suggest to ask for 20% to 50% more than an salary would yield (and ignore the additional risk and expenses they have).
Below you will find some numbers to help you calculate how high your hourly or daily rate should be.
- You take more risk than full time employees, phases without income are likely