How do I know if there will be a penalty if I don't do four equal amounts for tax payment (1040-es) ? I can't estimate in advance four equal amounts.

[nuxclass]

I would like to pay different amounts for each payment, I don't know my future income as real estate agent, so I won't be able to provide by April 15th and commit on the four equal amount.

[Ashby]

You do not have to make equal payments. The program automatically generates them as equal, but you are to pay your estimated taxes as you earn your income. I you have zero income in Q2, but $100K in Q4, you will pay zero in Q2 and make a large payment in Q4.

[nuxclass]

Form 1040 ES Instructions says "You can pay all of your estimated tax by April 15, 2019, or
in four equal amounts by the dates shown below." -> Is this a SHOULD or MUST ?

[Ashby]

It's a should. It's perfectly acceptable to use the "annualized method" and pay your estimateds when the money is earned.

[nuxclass]

Are you referring to " annualized income installment method" ?

[Ashby]

Yes.