Overall, estimated taxes are estimates calculated based on your income. Depending on how much you pay in quarterly estimated payments each quarter, you may owe some additional money in taxes at the end of tax season. You could also get money back at the end of tax season! Both circumstances are equally okay and to be expected.
It is entirely up to you if you want to pay more or less than the quarterly estimate Heard has calculated for you. If you feel like you may have some additional income not reflected in Heard and/or you want to pay a little extra to cover your bases, feel free to round up our estimate when you pay!
If you feel that the estimate is higher than what you anticipated owing in taxes this year, you may want to lower your estimate slightly. Underpaying the estimated tax can result in the IRS assessing an underpayment penalty, and interest is also applied based on each quarter in which underpayment occurred.
Lastly, a note from the IRS on tax liability and penalty fees:
"Generally, most taxpayers will avoid this penalty if they owe less than $1,000 in tax after subtracting their withholdings and credits, or if they paid at least 90% of the tax for the current year, or 100% of the tax shown on the return for the prior year, whichever is smaller."