What additional taxes do I owe?
That depends on your total income and whether your $14,553 gain is long term or short term. Long term capital gains (LTCG) are taxed at 0% until your taxable income reaches the 22% tax bracket. The portion of the LTCG in the higher bracket is taxed at 15%.
As others have suggested, you need to prepare an amended tax return.
For a quick look, you can try this tool: https://turbotax.intuit.com/tax-tools/calculators/taxcaster/?s=1.
https://turbotax.intuit.com/tax-tools/calculators/taxcaster/?s=1. Enter your regular income first to see the regular tax. Then add the sale to see the effect.
Enter the $14,553 as LTCG. Depending on how much total income you have LTCG are partially taxed at 0%, 15%, 20% and/or 23.8%.
