I did some contract coaching work for a university and received a one-time payment for the services rendered over 3 months. The amount taxed for Federal Withholding was a staggering 25%. For someone in my low income bracket (hourly wage of $12.50), I had only been paying 8.9% tax on federal income. Did I supply incorrect information?
This source claims that supplemental income is taxed at 25%. It's unclear to me whether coaching work is supplemental.
This source says that payments above or equal to $1,631 have a tax of 25% plus 211.65. However, my federal withholding is exactly 25% of the payment I received (no added 211.65), and it was not a semi-monthly pay cycle either.
Would I pay less money in taxes if the coaching services were payed semi-monthly?