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Free Income Tax Calculators (The Best in the USA!!)

Calculating your income taxes may seem like a daunting task. However, there are free income tax calculators available online which make it much easier for Americans to calculate their income taxes easily. All you have to do is input the numbers corresponding to your specific financial situation, like your annual income and filing status, and you get an estimated amount on how much income taxes you will owe in a given year.

We’re comparing three of the most popular free income tax calculators in the United States. Our picks are Casaplorer, NerdWallet, and SmartAsset.

We are comparing them based on the simplicity to use and the accuracy offered.

Looking for the best free income tax calculators? You’ve come to the right place! Let’s talk about them.

Best Free Income Tax Calculators for 2021Is there a free income tax estimator for Canada?

There is! While we’re going to talk about US calculators, there are a few free income tax options for Canada – our friends across the border. In fact, you actually have two great options.

The first is Turbo Tax’s Canada Calculator. This one is great and comprehensive, and perfect if you already use Turbo Tax!

The second option is from Wealth Simple. While this calculator isn’t as comprehensive as Turbo Tax’s, it is a great way to get a general idea of what you will get back or owe.

How do I calculate my taxable income?

To calculate your taxable income, you’ll need to take your gross income and subtract your tax deductions. Your gross income is ALL of the money you earned during the year (including your job, side hustles, and other income) before any taxes or deductions are taken out.

After subtracting any deductions that you have, you’ll have your “net” income. That is the taxable income that you’ll pay for. Then you’ll need to find your appropriate tax bracket based on your income and filing status to find what you owe. 

How do I calculate my tax manually?

Thinking you might be able to DIY your taxes? How could you calculate your taxes manually?

You would follow the steps in the section above, plus make sure you read up on current tax laws and follow those as well. This is a strenuous process and it is easier to use a calculator (or pay a CPA to do it for you!). 

Related: What Happens If You Underpay Your Taxes?

How much will I pay in taxes for 2021?

How much you pay in taxes for 2021 will depend on your possible deductions, dependents, and taxable income bracket. This is why a calculator is a must! It helps you know if you will pay taxes for 2021, or if you could possibly get a refund.

Related: What is the 2021 Stimulus Impact on Your Taxes? (a MUST read!!)

Free Income Tax Estimators for 2021

Now that you know more about tax estimating, let’s look at the best free income tax estimators for 2021.

NerdWallet Income Tax Calculator

Nerdwallet income tax calculator 2021

The income tax calculator by NerdWallet requires users to input the following information.


  • Income
  • Filing status – Single, Married (Filing Jointly), Married (Filing Separately), Head of Household
  • Age
  • Number of dependents you claim
  • Traditional 401(k) contributions
  • Traditional IRA contributions
  • HSA contributions
  • Other contributions
  • Itemized deductions
  • Tax paid or withheld
  • Option to declare whether you are
    legally blind
  • Option to declare whether your
    spouse is 65+ or legally blind

Not Included: 

  • State you live in
  • City you live in

NerdWallet accounts for the users’ 401(k) and IRA contributions. It’s easy to use the calculator too.

NerdWallet is also the only calculator out of the three that offers the user to choose between four different filing statuses. This feature can generate more accurate results.

However, NerdWallet does not account for the taxes charged at the state and local levels, which the other calculators do.

As far as the results section goes, by using NerdWallet’s Tax Calculator, you will be able to calculate the following:

  • Taxable income
  • Effective tax rate
  • Estimated federal taxes
  • Federal taxes withheld
  • Total owed

Comparing these results with the ones provided by Casaplorer and SmartAsset, it’s clear that the others give the user more insight.

NerdWallet does not break down the taxes for each state. So income taxes are underestimated because they do not include state-level taxes and local taxes.

Although, what NerdWallet does account for, compared to the other calculators, is the federal taxes withheld. If a portion of your taxes has already been withheld, then your final obligation will be smaller.

Related: Tips for Acquiring the Biggest Tax Refund

Casaplorer Income Tax Calculator

Casaplorer income tax calculator

The Casaplorer Income Tax Calculator makes it easy for users to know what they need to input.


  • State you live in
  • Household gross income
  • Filing Status – Single or Married/Qualified Widow(er)
  • Option to itemize deductions
  • Option to declare whether you are 65+ or legally blind

Not Included: 

  • The city you live in
  • IRA contributions
  • 401(k) contributions
  • HSA contributions
  • Other contributions
  • Two filing statuses
  • Number of dependants
  • Option to declare whether your
    spouse is 65+ or legally blind

Casaplorer makes it easier for users who are looking for an estimation of their income taxes. On the other hand, they don’t have options for 401(k) contributions, IRA contributions, or the number of dependents.

However, if you haven’t made any contributions towards these accounts and don’t have any dependents, then this calculator will give you great results.

Through the Casaplorer Income Tax Calculator, you will be able to get the following info:

  • Federal Income Tax
  • State Income Tax
  • FICA Taxes
  • Total Income Taxes
  • Effective Tax Rate
  • Take-Home Income

Casaplorer is more insightful than NerdWallet because they give a full breakdown of the taxes you will have to pay on the federal and state level. However, the third calculator SmartAsset accounts for differences in the local level and gives the marginal tax rate and effective tax rate for each level.

Related: Tips for Maximizing Your Retirement Savings and Decreasing Taxes

SmartAsset Federal Income Tax Calculator

SmartAsset free income tax calculator

Last but not least, if you use the SmartAsset income tax calculator, you will be required to complete the following.


  • Household income
  • Location
  • Filing status – Single/Married
  • 401(k) contribution
  • IRA contribution
  • Itemized deductions
  • Number of state personal exemptions

Not Included: 

  • Two filing statuses
  • Age
  • Option to self-declare if you are legally blind
  • Option to declare whether your spouse is 65+ or legally blind
  • HSA contributions
  • Other contributions

In terms of simplicity, it’s easy to add your information on SmartAsset’s calculator. Plus, similar to NerdWallet, SmartAsset allows you to add your IRA and 401(k) contributions and offers a high level of accuracy.

However, it doesn’t include the age of the individual using the calculator. So, a user 65 years old or older would have to pay the same taxes as someone younger, which isn’t correct.

The SmartAsset Calculator also doesn’t account for federal taxes already being withheld. Plus, SmartAsset’s results are more detailed. Not only are the taxes broken down, but the calculator also gives you the specific marginal and effective tax rate for each jurisdiction.

Here is the summary of the results offered:

  • Federal Taxes
  • State Taxes
  • Local Taxes
  • FICA
  • Total Income Taxes
  • Income After Taxes
  • Retirement Contributions
  • Take-Home Pay
  • Marginal Tax Rate for each level
  • Effective Tax Rate for each level

Related: How to Save Money on Taxes

Free Income Tax Calculators: Which Is Your Favorite?

In conclusion, comparing the three calculators across the three dimensions of simplicity, accuracy, and number of features offered, we would rank Casaplorer first in terms of simplicity to use, SmartAsset would take the lead in terms of accuracy of results, and NerdWallet would rank highest in the number of features.

Simplicity Accuracy Features
1.    Casaplorer

2.    NerdWallet

3.    SmartAsset

1.    SmartAsset

2.    Casaplorer

3.    NerdWallet

1.    NerdWallet

2.    SmartAsset

3.    Casaplorer

The smaller number of inputs of Casaplorer makes the process easier for users, and since it takes into account the state-level taxes, we would argue that it is somewhat more accurate than NerdWallet, even though the latter includes a range of contributions.

On the other hand, SmartAsset provides a detailed breakdown of the user’s income taxes under each jurisdiction, placing it above other calculators as far as accuracy goes. Although, the number of outputs provided by SmartAsset can cause users to be overwhelmed by the results. For this reason, we have ranked SmartAsset the lowest in terms of simplicity.

Lastly, NerdWallet has the highest number of inputs and features, which place it first, followed by SmartAsset, and lastly, Casaplorer.

Which is your favorite free income tax calculator? Why? Tell us in the comments below!

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AUTHOR Kimberly Studdard

Kim Studdard is a project manager for online entrepreneurs and small businesses. When she isn't spending time with her daughter and husband, or reading her growing pile of horror books, you'll find her working on her HR degree and working towards FIRE.

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