USA Federal Income Tax Calculator
Tax Year
Tax Filing Status
Wages/Salaries (box 1 in W2)
Federal Tax withheld (box 2 in W2)
Social Security Wages (box 3 in W2)
Social Security Tax withheld (box 4 in W2)
Medicare Wages (box 5 in W2)
Medicare Tax withheld (box 6 in W2)
Taxable Interest (line 2b on Form 1040 for year 2018)
Qualified Dividend (line 3a on Form 1040 for year 2018)
Ordinary Dividend (line 3b on Form 1040 for year 2018)
Short term Capital gain/loss
Long term Capital gain/loss
Capital loss carryforward from previous years (enter as negative number)
property tax paid (if you own house)
Mortgage interest paid (if you own house)
Charity contribution to temple/school/etc
state income tax paid
State sales tax paid
Child Dependents (kids for tax purpose)
Other Dependents (parents for tax purpose)
AGI (line 11 on form 1040 for year 2020)
Itemized or Standard Deduction (line 12 on form 1040 for year 2020)
Taxable income (line 15 on Form 1040 for year 2020)
Taxable income subject to regular tax rate
Tax on income subject to regular tax rate
Taxable income subject to lower tax rate
Tax on income subject to lower tax rate
Investment income subject to NIT
Net Investment Tax (NIT) on investments
Supplemental Medicare tax
Child + other dependent credit (line 12 on Form 1040)
Tax assuming no AMT
AGI for AMT purpose (after itemizing)
taxable income for AMT purpose (after std deduction)
possible Tax if calculated under AMT
Extra AMT (if AMT tax was more than regular tax)
Total Federal Tax (line 24 on Form 1040 for year 2020)
Federal Tax Refund (line 34 or line 37 on Form 1040 for year 2020)
Social security tax
Social security tax Refund
Medicare tax
Medicare tax Refund
Total Tax Refund (line 34 or line 37 on Form 1040 for year 2020)
Capital loss carry forward (for next year)

Federal Income Tax Caculation

This calculator is to find out Your federal income tax for income within USA for 2018 to 2026. With a lot of changes in tax law starting from 2018, I had to modify the calculator. The calculator for years 2017 and before is now a separate calculator on the same page. Std deduction has been doubled while personal exemption has been eliminated, resulting in net wash (So, there is little incentive to itemize deductions). However, $2K child credit has been added for every dependent child, so that helps, resulting in lowering taxes by about 5% compared to earlier years.

Form 1040 which is the final tax form used to submit your tax return has changed completely for 2018, where it's very simple 1 page with only 23 lines in it. However, number of lines keep increasing every year, so we may be back to long IRS forms pretty soon. From 2019, tax form went to 2 pages. IRS 1040 form for selected year is here:

These are some of the other forms that you will frequently be using when filing your income tax return:
  1. Schedule B for form 1040 => Needed to report interest and dividends from stocks
  2. Schedule D for form 1040 => Needed to report capital gain from stocks
  3. Form 8889 => This is used to report your contribution to HSA, and qualified distributions taken out of them
  4. Form 8959 => Additional Medicare tax => This is for high earners (AGI > $250K) where they need to pay additional medicare tax
  5. Form 8960 => NIT tax => This is again for high earners only.
  6. Schedule 2 for form 1040 => This combines additional taxes from all other forms such as Form 8959, 8960, etc.
It's a very simplistic calculator. It's only meant for people who are married, filing jointly, have only one working memeber and have a combined income between $100K - $500K. So, tax filing status only shows returns which are "married filing jointly", with only one W2 form. Calculator might still work for people making < $100K or more than $500K, but there are lot more credits at lower income, and lot more expiring deductions at higher income, which my calculator doesn't take into account. Nevertheless it can still give you a ballpark number. My calculator doesn' account for any extra payments sent out by government, or any new tax laws enacted as a one time thing during recessions etc.

Calculator also shows Social security tax and medicare tax but not state income taxes. Note that social security tax and medicare tax have nothing to do with federal income tax, but you still fill that info with your income tax. These are used to figure out if you overpaid for them This can happen for social security tax in situations where you have multiple jobs in a year, and each employer deducts social security tax assuming that's your only job. Excess payment for medicare tax is more common, as there is extra medicare tax for higher income, and employers usually deduct more than what they are supposed to deduct. Calculator also shows any child credit that you receive for kids or other dependents.

Calculator doesn't show any Premiums you pay for healthcare or contributions to HSA/FSA accounts. This is because all that money is taken out from your paycheck pre-tax, and hence your W2 earnings don't even show that. Also, your 401K retirement contrbution or your Employer's contribution are not shown in Calculator as they are taken out of your paycheck pre-tax, and hence your W2 earnings don't even show that. However, for 401K contributions, you still have to pay social securit and medicare taxes, so they show up in your social security wages (box 3) and medicare wages (box 5). That is why your medicare taxes are always higher than wages, if you made any 401K contribution in that particular year.

This is how to use the calculator.

For most simplistic returns, only info from W2 form needs to be filled, since there are no other income sources. Enter the correct number of kids + other dependents, and leave all other entries at default of 0. For more involved forms, you will need to enter your income from other sources as stocks, banks, etc. You will usually get tax statements from all the places that will show you exactly how much money they paid you. You just have to enter the number from all those tax statements. Click on "calculate" to see the results.

  • Enter Wages/Salaries from your W2 form box. If multiple W2 forms from one or both partners, add up wages. SS and medicare should be entered separately for each spouse, to check if either of them overpaid. Any excess SS tax paid will show up as credit on line 17 of form 1040
  • Enter Total Interest that you received from banks/brokerage firms
  • Enter Dividend and any capital gain/loss from your stock sale (short term is for stocks held less than a year). All dividends entered here are considered qualified dividend (i.e lower tax rate applies on them). This is true for most of the stock dividend you receive
  • If you own house, enter Propery tax and Mortgage interest paid
  • Enter all charity contribution, state income tax paid and all sales tax paid. If you do not want to save all sales tax receipt, you can use IRS sales tax calculator on to give you a standard sales tax amount that you can use to deduct. The amount you get from there is usually much higher than the sales tax that you would have paid, so it's advisable to use standard sales tax amount
  • Enter dependents (include you, your spouse, your kids, and any other dependent who passes "residency test".
  • Enter Federal/SS/Medicare tax withheld from your paycheck. This is used to estimate your refund.