Capital gains on primary

[Melinda Heizenrader]

Would like some info on capital gains

Scenario.

-Purchase price $250,000

-Cash out refinance 10 years later new morgage is $450,000 appraisal 750,000

-Used the $ to invest in more Realestate.

- Decide to sell a few years later house and property should sell close to $1 million .

My question is do you figure the capital gains from the original purchase prize or the refinanced ? I will seek advice from our tax professional before we do decide to sell . Curious if anyone any info .

Thank you!