GaryG1
Intuit Alumni

Get your taxes done using TurboTax

As part of submitting you extension you should be providing estimated taxes owed. 

TurboTax Easy Extension can help you submit your extension including calculating your tax refund\owed:  https://turbotax.intuit.com/irs-tax-extensions/

You can also use the stand-alone TaxCaster Calculator: https://turbotax.intuit.com/tax-tools/calculators/taxcaster/