Yes, all income must be reported on your tax return. The $400 threshold means that you will not be subject to SE taxes on the income.
It is a common misconception that
if a taxpayer does not receive a Form 1099-MISC or if the income is under $600
per payer, the income is not taxable. There is no minimum amount that a
taxpayer may exclude from gross income.
All income earned through the
taxpayer’s business, as an independent contractor or from informal side jobs is
self-employment income, which is fully taxable and must be reported on Form
1040.
Use Form 1040, Schedule C, Profit or Loss from Business, or Form 1040, Schedule C-EZ, Net Profit from Business (Sole Proprietorship) to report income and expenses.
Taxpayers will also need to prepare Form 1040 Schedule SE for self-employment
taxes if the net profit exceeds $400 for a year. Do not report this income on
Form 1040 Line 21 as Other Income.
Independent contractors must report
all income as taxable, even if it is less than $600. Even if the client does
not issue a Form 1099-MISC, the income, whatever the amount, is still
reportable by the taxpayer.
Fees received for babysitting,
housecleaning and lawn cutting are all examples of taxable income, even if each
client paid less than $600 for the year. Someone who repairs computers in his
or her spare time needs to report all monies earned as self-employment income
even if no one person paid more than $600 for repairs
From
<https://www.irs.gov/uac/reporting-miscellaneous-income
