I was sent a penalty from IRS of 501.57$ for failure to pay proper estimated tax. Turbotax says I owed 15483, while they say I owe 15611.00

[Opus 17]

Is that "owed" the final tax, the estimated tax, or the penalty?  I can't follow your numbers.  Is the IRS saying the penalty calculation is wrong or that the tax calculation is wrong?

[Critter]

TT calculates an estimated underpayment penalty based on your entries in the program  however the feds & state reserve the right to access a final underpayment penalty, late filing penalty or late paying penalty ( plus interest ) based on the info they have and when the balance due was actually paid.     https://www.irs.gov/individuals/understanding-your-cp14-notice