CGT on selling an investment property, that I originally bought as my main residence?

I originally bought a unit to live in, around 5 years ago, for $150,000.
3 years ago I started renting it out, now I want to sell it for around $232,000.
is CGT based on the purchase price of $150,000 even though I bought it as my main residence? or is there some formula to work it out based on when I actually turned it into an investment property?

I originally bought a unit to live in, around 5 years ago, for $150,000. This unit is in both me and my partner's names.
3 years ago I started renting it out, now I want to sell it for around $232,000.
is CGT based on the purchase price of $150,000 even though I bought it as my main residence? or is there some formula to work it out based on when I actually turned it into an investment property?
Also, could some one figure out the "worse case" of how much I would have to pay back, based on $82000 "profit", me and my partner have an approx. combined income of $90k-$100k per annum?
And, does the ATO have some sort of re-payment plan ?

You can pro-rate the gain against the total time you owned it to the time it was rented. Based on your explanation this would be 3/5 of the time that it was not your principal residence. Also include in your purchase price the amount of legal fees (purchase & sale), stamp duty (purchase) and commissions (sale) that were paid. This figure will then be deducted from the sale price. For owning it longer than 12 months you will get a 50% exemption in the capital gains payable. So assuming you have no more costs to add to the figures you have provided the outcome will be a capital gain of $82,000 less $41,000 (50% reduction) and multiply by 3/5 for the time you lived in the unit yourself. This will leave you with a final capital gain of $24,600 which is added to your taxable income. As the unit is owned by you and your partner the $24,600 will be split between you both and assessed in your own returns i.e.$12,300 each. Assuming you are both on the 30% tax rate and will remain in that bracket with the capital gain added to your income you will be looking at paying $3874.50 each including medicare levy on the gain.
If you do have trouble paying back a debt to the ATO you may be able to organise a payment plan of your debt based upon your circumstances. Each person is different though so you will have to contact them to determine your particular circumstances.

Hi there,
Some good news for you.
If you elect the unit as your main resident and you rented it out, the capital gain will be exempt under main residence exemption (rent out for less than 6 years period)