Estimated tax is the method used to pay taxes on income that is not subject to withholding (for example, self-employment earnings, interest, dividends, rent, alimony, etc.). In addition, if you do not elect voluntary withholding, you must make estimated tax payments on other taxable income, such as unemployment compensation and the taxable portion of your Social Security benefits.
The U.S. tax system operates on a pay-as-you-go basis. This means that taxpayers need
to pay most of their tax during the year, as the income is earned or received. Taxpayers
must generally pay at least 90 percent (however, see 2018 Penalty Relief, below) of
their taxes throughout the year through withholding, estimated or additional tax
payments or a combination of the two. If they don’t, they may owe an estimated tax
penalty when they file.

The IRS has seen an increasing number of taxpayers subject to estimated tax penalties, which apply when someone underpays their taxes. The number of people who paid this
penalty jumped from 7.2 million in 2010 to 10 million in 2017, an increase of nearly 40 percent. The penalty amount varies but can be several hundred dollar.

Who may need to pay estimated taxes?

Individuals, including sole proprietors, partners and S corporation shareholders, may
need to make estimated tax payments if:

• they expect to owe at least $1,000 when they file their tax return.
• they owed tax in the prior year.
  Taxpayers who may need to make estimated tax payments include someone who:
• receives income that isn’t from an employer, such as interest, dividends, alimony,
  capital gains, prizes and awards.
• has tax withheld from their salary or pension but it’s not enough.
• has more than one job but doesn’t have each employer withhold taxes.
• is self-employed.
• is a representative of a direct-sales or in-home-sales company.
• participates in sharing economy activities where they are not working as
  employees.

For estimated tax purposes, a year has four payment periods. Taxpayers must make a
payment each quarter. For most people, the due date for the first quarterly payment is
April 15. The next payments are due June 15 and Sept. 15, with the last quarter’s
payment due on Jan. 15 of the following year. If these dates fall on a weekend or
holiday, the deadline is the next business day.
Farmers, fishermen and people whose income is uneven during the year may have different rules.

Generally for this declaration they use Form 1040 to calculate the estimated tax.
Resident aliens use Form 1040-ES (NR) to calculate estimated tax.

Taxpayers can pay online, by phone or by mail.
Finally, if a taxpayer does not pay enough or pays late, a penalty will apply.
Basics of estimated taxes for individuals Internal Revenue Service. Available
at: https://www.irs.gov/es/newsroom/basics-of-estimated-taxes-forindividuals