What is Taxable Income and How Do You Calculate It?

Many people treat salary, total earnings, and taxable income as interchangeable terms. In the eyes of the government, however, they’re distinctly different things, and confusing them can lead to overpaying or underpaying your taxes. What you need to be paying is your taxable income, and the good news is that it’s usually lower than your salary and total earnings.

Taxable income is the portion of your total earnings that remains after taking all legally allowable adjustments and deductions. It’s the final number that the government uses to calculate your income tax liability for the year.

How to Calculate Your Taxable Income

Calculating your taxable income requires a three-step reduction process. Let’s get into it.

Start with Gross Income

The first step is establishing your gross income. This is the broadest category of income and includes just about all the money, property, or services you receive unless specifically excluded by tax law. That includes:

• Wages, salaries, tips, and commissions from employment.
• Interest and dividends received from bank accounts or investments.
• Capital gains from the sale of stocks, real estate, or other assets.
• Rental property income (before deducting expenses).
• Business or self-employment income.
• Taxable retirement distributions.

Money that’s excluded from this calculation include:

• Gifts and inheritances received.
• Qualifying distributions from Roth IRAs.
• Child support payments received.
• Interest earned on municipal bonds.
• Compensation for injuries or sickness.

Adding up all of your taxable gross income will give you your starting point.

Calculate Adjusted Gross Income (AGI)

Next, it’s time to calculate your adjusted gross income (AGI). This number is very important because it’s used to determine your eligibility for tax credits and other deductions. This is where you subtract specific allowable deductions, often referred to as “above-the-line” adjustments, because they appear on the first half of the tax form.

Some key above-the-line adjustments include:

• Traditional IRA contributions: Money you contribute to a traditional IRA (up to the annual contribution limit).
• Student loan interest paid: A limited amount of interest paid on qualified student loans can be deducted.
• Self-employment tax: If you are self-employed, half of the self-employment tax you pay is deductible here.
• Health Savings Account (HSA) contributions: Contributions made to an HSA are also deducted.
• Alimony paid: For divorce agreements executed before 2019, alimony payments are deductible.

Your gross income minus above-the-line adjustments gives you your AGI.

Add Deductions

Finally, you have to take your deductions. Every taxpayer must decide between the standard deduction and itemizing deductions. You should choose the option that results in the largest reduction to give yourself the lowest tax liability.

In 2025, the standard deduction is $15,750 for single filers or married and filing separately, $31,500 for married filing jointly, and $23,625 for head of household. About 90% of filers take the standard deduction because it’s much simpler than itemizing deductions and requires no documentation of expenses.

If you choose to itemize deductions, you’ll need to add up all of your tax-deductible expenses throughout the year and make sure you have receipts to document them in case of an audit. Common itemized deductions include mortgage interest, charitable contributions, and medical and dental expenses that exceed a specific percentage of your AGI.

The Taxable Income Calculation

When you have your AGI and choose the optimal deduction, it’s simple enough to calculate your taxable income. It’s simply your AGI minus your deductions. So, if you had an AGI of $100,000 and took the $15,750 standard deduction for single filers, your total taxable income would be $84,250.

This final taxable income number is the foundation of your tax return. It’s the amount that the IRS will apply tax rates to to determine how much you owe (or are due in a refund).

Tax Brackets and Rates

Your taxable income is taxed using a marginal tax system. That means your income is divided into segments, or “brackets,” and each segment is taxed at a different rate.

For example, the first $10,000 of your taxable income might be taxed at 10%, the next $30,000 at 12%, and so on. This is why your effective tax rate (the total percentage of your income you actually pay) is always lower than the rate of the highest bracket you reach.

Pro tip: after you’ve calculated your tax liability based on your taxable income, you can still subtract tax credits. Credits, unlike deductions, are applied directly against the tax you owe as a dollar-for-dollar reduction of your final tax bill. So, if you found that you owed $1,000, a $2,200 child tax credit would turn it into a $1,200 refund.