How much penalty do I have to pay for my Roth IRA conversion when doing tax filing?

Hi, I just did a Roth IRA backdoor conversion in Jan. 2023 after I changed job.  I have a normal paycheck tax withheld every month now.  How much penalty will incur when I file the tax return and pay the additional tax (I will probably owe $21K federal and $5K  MA income tax for this conversion) in April 2024?  How can I avoid this late payment penalty?