I recently took a contract-to-hire position through a contracting agency. I was an established PHP developer, but the company I'm doing work for now is a Ruby on Rails shop which was seeking intermediate developers to train under their senior-level people, for a 6 month contract. In my local market, Ruby on Rails developers are hard to come by; because of this, CTH is ideal for their situation as it allows them to try converting people from other disciplines like mine without making an immediate commitment in case things don't work out.
Before even being presented to this company, the contracting firm negotiated an hourly rate of $34/hr, with a conversion after 6 months to full-time employee at a salary of $65k. This opportunity seemed promising, I was looking for a significant change from my previous job, and I loved the environment at the new company. I'm nearing the end of my contract period, and things are going great. I fit in well with the company culture, I've learned the ins and outs of the new language without issue, and I'm definitely contributing much more than the other 2 people who were hired at the same time as me under similar terms.
However, I feel like the agreed upon conversion rate ($65k) is lower than I'm worth. I understand that with a FTE position, I get added benefits such as health insurance and paid time off, but market rate for similar positions in this area are in the $75-85k range. I'm also fairly confident that the full-time employees here are earning within that range.
When my contract nears a close, am I in any position to try to negotiate for a higher salary? On one hand, the conversion rate was agreed upon beforehand. I also had to interview multiple times before being given an official offer, as I didn't do well in my first interview and there were definite concerns about whether I could handle the new field. Along with this, I'm averaging nearly 50 hours a week as a contractor; to take the agreed upon salary wouldn't just be slightly less than my current take home amount, it would be another 20-25% less as an effective hourly rate because of the additional hours I'm putting in (and assume would be expected to continue to log as a salaried FTE). Because of these reasons, I feel that I can justify asking for $5000-15000 more to be in line with market rates based on my performance, but I don't know if that will be frowned upon for trying to renegotiate something that was pre-determined.