@barbaranordlund
IRS requires you to estimate your total tax for the year and pay as you go.
Assuning you have no W-2 withholding nor other withholding,
you can base your estimate on prior year's tax , or 90% of this year's tax, whichever is smaller.
each quarter your estimated tax paid and withheld should be at least 25% of the estimate, even if your income is uneven,
if your estimate is based on this year's tax and turns out to be wrong you may be penalized.
you can compensate by overestimating.
if your estimate is based on prior year's tax, you know that when you file by April 15, which is also the first estimated tax payment due date. How convenient.
This is the simplified method.
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When to pay — Estimated tax payments are due four times a year:
April 15 for payment period January 1–March 31
June 15 for payment period April 1–May 31
September 15 for payment period June 1–August 31
January 15 for payment period September 1–December 31
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If your quarterly withholding and estimates in 2023 are at least 100% / 4 = 25% ( 110% / 4 for certain high income taxpayers) of your 2022 tax, there will be no penalty on your 2023 tax return, regardless of any jump in income.
you are protected from a sudden capital gain or spike in income at year end.
For further info on uneven income and uneven payments to IRS, see Instructions for Form 2210.
