How much Capital Gains Tax will I need to pay on my rented property if i sell?

CGT is 18% for basic rate taxpayers or 28% for higher rate taxpayers. You have an exempt allowance of £10,600 per year.If you moved back into the property for a while, there would be no CGT as it would be your main residence. You really need some specialist tax advice here.

Technician territory without a doubt. In theory (many many variations) any gains up to you moving out go under "primary personal residence" and you would be liable for the change in value while it was rented out. Less CGT allowance and charged at the appropriate band. I assume you are in Self Assessment and reporting the "Income From Property" by your Yax Return. You realy need to talk to an HMRC technician or even pay an accountant (preferablly a property specialist) about it.

Do you have permission to let from your lender? The CGT payable will depend on the vale of the property in Jan 2010. It is unlikely to have gone up more than £20k in the last 2 years so there should be no CGT if you have no made any other capital gains in that period.

The time when you lived it the property as your main residence is covered by Private Residence Relief. Also covered is the last 3 years of ownership. It seems that you have owned the property for 14 years and lived in it for 10 years. That means that 13 years (10 + final 3) worth of the gain is covered by PPR. If you sold it tomorrow your gain would be £100,000 (£150K - £50k). Your PPR relief would be £92,850 (13/14 x £100k) Your gain would be £7,150. However, you would also be entitled to additional relief up to £40K because you had let the property, so the gain would be NIL.