I am currently looking for a job as a developer in Sydney, Australia and one of the positions I'm considering is a 3-month contract. They asked me what my expected daily rate would be. With full time / permanent positions, my expected salary would be 120k per year + 9.5% superannuation (Australian retirement fund, 9.5% is the standard rate).

How much should I ask per day, for a 3 months contract? I have never interviewed for contract positions and have no idea of how much "mark-up" you add to your "base salary", to make up for the fact that you don't have paid leave and you have less "certainty".