Science, Tech, Math › Math Calculate Federal Income Tax Share Flipboard Email Print Math Math Tutorials Geometry Arithmetic Pre Algebra & Algebra Statistics Exponential Decay Functions Worksheets By Grade Resources View More By Jennifer Ledwith Math Expert B.B.A., Finance and Economics, University of Oklahoma Jennifer Ledwith is the owner of tutoring and test-preparation company Scholar Ready, LLC and a professional writer, covering math-related topics. our editorial process Jennifer Ledwith Updated July 03, 2019 The average American wants to share as little of his or her earnings with Uncle Sam. How does the saying go? Don’t tax you. Don’t tax me. Tax that man behind the tree. Gnawing on a worker’s wages, income tax is an everyday example of percent decrease at work. This article focuses on using percents to calculate disposable income, the amount of money that remains after paying federal income tax. How to Calculate Income Tax When you get that first real job and learn that you’ll have an annual salary of $36,000, realize that you don’t have $3,000 a month to spend.Let’s say that your income tax rate will be 5%. What will be your disposable income?1. Find the amount of taxes that you’ll pay.36,000 * .05 = $1,8002. Subtract the amount of taxes from your income.$36,000 – $1,800 = $34,200Disposable Income: $34,200Disposable Income per Month: $34,200/12 = $2,850Don’t run out and get a mortgage and car note that total $2,500 a month. Otherwise, you will be the hungriest person living the American Dream. Exercises Answers and Explanations Use each annual salary and tax rate to calculate disposable income.1. Annual salary: $350,000Federal income tax rate: 28%Disposable income: 2. Annual salary: $10,000Federal income tax rate: 5%Disposable income: 3. Annual salary: $80,500Federal income tax rate: 10%Disposable income: 4. Annual salary: $175,000Federal income tax rate: 23%Disposable income: 5. Annual salary: $50,400Federal income tax rate: 10%Disposable income: 6. Annual salary: $93,550Federal income tax rate: 18%Disposable income: 7. Annual salary: $27,950Federal income tax rate: 5%Disposable income: Cite this Article Format mla apa chicago Your Citation Ledwith, Jennifer. "Calculate Federal Income Tax." ThoughtCo, Jan. 29, 2020, thoughtco.com/calculate-federal-income-tax-2312468. Ledwith, Jennifer. (2020, January 29). Calculate Federal Income Tax. Retrieved from https://www.thoughtco.com/calculate-federal-income-tax-2312468 Ledwith, Jennifer. "Calculate Federal Income Tax." ThoughtCo. https://www.thoughtco.com/calculate-federal-income-tax-2312468 (accessed February 27, 2021). copy citation