According to my calculations, you could have an additional $7300 of long term capital gains or a total of $19215 long term capital gains before owing any tax. This assumes all your interest and dividends are taxable at ordinary income tax rates. I assumed you are filing Single and use the standard deduction.
This is based on 2019 tax rates and standard deduction but 2020 tax rates aren't expected to be much different. I'd suggest you get other opinions before relying on this because it is always possible that I could have made a mistake in the trial tax return I prepared for your situation.
If you use the CD/download product to prepare you tax return, there is a very handy tool you can use to estimate taxes for next year. Switch to Forms mode and type what-if in the open form box and click on what-if worksheet to bring up a worksheet where you can enter estimated 2020 information.
In either the online or CD/download product, you can use the tool within your 2019 tax return to calculate estimated taxes for next year. To find it type estimated taxes for next year in the search box and click on jump to estimated taxes for next year. Say No to changing the W-4 and continue on.
