How to Use This Calculator
- 1
Enter Initial Investment
Input the lump sum amount you're starting with in both the taxable account and the IRA.
- 2
Specify Annual Contribution
Enter the amount you plan to add to the account each year. Remember IRA contribution limits typically apply (e.g., $7,000 for 2024, $8,000 if 50+).
- 3
Set Annual Growth Rate
Input your expected average annual investment return as a percentage (e.g., 7% for a diversified portfolio).
- 4
Define Investment Period
Enter the number of years you plan to keep the money invested before withdrawal.
- 5
Input Capital Gains Tax Rate
Enter your expected long-term capital gains tax rate, which applies to profits in the taxable account (e.g., 15% for many income levels).
- 6
Specify IRA Withdrawal Tax Rate
Enter your expected ordinary income tax rate at the time you anticipate withdrawing from your IRA (e.g., 20% in retirement).
- 7
Choose IRA Account Type
Select whether you are comparing against a Traditional IRA (tax-deferred growth) or a Roth IRA (tax-free growth).
- 8
Review Account Performance
The calculator will display which account type is recommended, the net after-tax values, and the IRA's advantage.
Example Calculation
An investor with $10,000 initially, contributing $2,000 annually at a 5% growth rate over 20 years, faces a 15% capital gains tax and a 20% IRA withdrawal tax, choosing a Traditional IRA.
Initial Investment Amount ($)
10,000
Annual Contribution ($)
2,000
Annual Growth Rate (%)
5
Investment Period (years)
20
Capital Gains Tax Rate (%)
15
IRA Withdrawal Tax Rate (%)
20
IRA Account Type (select)
traditional
Results
$80,217.47
Tips
Consider Your Future Tax Bracket
The choice between a Traditional IRA (tax-deferred) and a Roth IRA (tax-free withdrawals) largely hinges on whether you expect to be in a higher or lower tax bracket in retirement. If you anticipate a higher bracket, Roth is often superior. If lower, Traditional may offer better upfront tax savings.
Maximize IRA Contributions Annually
IRAs offer significant tax advantages. In 2025, the contribution limit for IRAs is $7,000 (or $8,000 if age 50 or older). Maximizing these contributions before contributing to a taxable account can dramatically improve your long-term after-tax returns due to tax-deferred or tax-free growth.
Understand Roth IRA Income Limits
While Roth IRAs offer tax-free growth, there are income limitations for direct contributions. For 2025, if your Modified Adjusted Gross Income (MAGI) exceeds certain thresholds (e.g., $161,000 for single filers), you may need to use a 'backdoor Roth' strategy to contribute, which involves contributing to a Traditional IRA and then converting it.
Comparing After-Tax Returns: Taxable vs. IRA Accounts
The Taxable Account vs. IRA Calculator provides a detailed comparison of investment growth and net after-tax returns between a standard taxable brokerage account and either a Traditional or Roth IRA.
For long-term investors planning for retirement or other significant financial goals, understanding the impact of tax efficiency is paramount.
In 2025, with IRA contribution limits at $7,000 (or $8,000 for those 50 and over), leveraging these tax-advantaged accounts can significantly outperform taxable alternatives over decades, especially when factoring in the power of compounding.
How Tax Efficiency Drives Long-Term Investment Growth
Tax efficiency is a cornerstone of successful long-term investing, profoundly impacting your eventual wealth accumulation.
In a taxable brokerage account, capital gains, dividends, and interest are often subject to taxes annually or upon sale, creating "tax drag" that eats into your returns.
Conversely, IRAs offer tax-advantaged growth, allowing your investments to compound more effectively.
Traditional IRAs defer taxes until retirement, while Roth IRAs provide tax-free withdrawals in retirement.
This difference, particularly over an investment horizon of 10, 20, or even 30 years, can result in tens or even hundreds of thousands of dollars more in your pocket, making the choice of account type a critical financial decision.
Exploring IRA Account Types and Their Tax Impact
This calculator evaluates the performance of three primary investment vehicles: a standard taxable brokerage account, a Traditional IRA, and a Roth IRA.
The core logic involves projecting the future value of investments in each, then applying the relevant tax rules.
For a Taxable Account:
Annual Taxable Gain = (Previous Year End Value + Annual Contribution) × Annual Growth Rate
Capital Gains Tax = Annual Taxable Gain × Capital Gains Tax Rate
Taxable Account Value (Year N) = Previous Year End Value + Annual Contribution + Annual Taxable Gain - Capital Gains Tax
For a Traditional IRA:
Traditional IRA Value (Year N) = (Previous Year End Value + Annual Contribution) × (1 + Annual Growth Rate)
Withdrawal Tax = Traditional IRA Value (at withdrawal) × IRA Withdrawal Tax Rate
Net Traditional IRA = Traditional IRA Value (at withdrawal) - Withdrawal Tax
For a Roth IRA:
Roth IRA Value (Year N) = (Previous Year End Value + Annual Contribution) × (1 + Annual Growth Rate)
Roth withdrawals are tax-free, assuming qualified distributions.
The calculator then compares the net after-tax values to recommend the most advantageous option.
Comparing a Traditional IRA to a Taxable Account
Let's consider an investor starting with an initial $10,000, contributing $2,000 annually at a 5% average annual growth rate over 20 years.
They anticipate a 15% long-term capital gains tax rate for the taxable account and a 20% ordinary income tax rate for Traditional IRA withdrawals in retirement.
- Project Taxable Account Growth: Each year, the taxable account grows, and capital gains tax is applied to realized gains (or assumed for simplicity). Over 20 years, the compounded effect of paying capital gains tax will reduce the overall net return.
- Project Traditional IRA Growth: The Traditional IRA grows tax-deferred for 20 years. All contributions and earnings compound without annual tax drag.
- Calculate After-Tax Values:
- Taxable Account (Net After Tax): After 20 years, the gross value is calculated, and capital gains tax is applied to the total appreciation. For the given example, the estimated net after-tax value would be approximately $68,767.47.
- Traditional IRA (Net After Tax): The total accumulated value after 20 years, approximately $100,271.84, is then subjected to the 20% withdrawal tax.
Withdrawal Tax = $100,271.84 × 0.20 = $20,054.37Net Traditional IRA = $100,271.84 - $20,054.37 = $80,217.47
In this scenario, the Traditional IRA provides a net advantage of approximately $11,450 over the taxable account ($80,217.47 - $68,767.47).
Formula Variants for Retirement Account Comparisons
When comparing taxable accounts to IRAs, several formula variants or assumptions can be used, particularly regarding how capital gains tax is applied in the taxable account.
The most common approach, used here, assumes capital gains tax is paid annually on realized gains or accrued gains (often a simplification for modeling purposes).
However, a more precise approach for long-term taxable accounts might assume taxes are only paid when investments are sold, leading to greater tax deferral within the taxable account itself.
Another variant considers the "tax on dividends" separately, which are typically taxed at ordinary income rates or qualified dividend rates annually.
For Roth IRAs, the primary variant is often the "backdoor Roth IRA" strategy, where contributions are made to a non-deductible Traditional IRA and then converted to a Roth, allowing high-income earners to bypass direct Roth contribution limits, which can be over $161,000 for single filers in 2025.
This calculator uses a simplified annual capital gains tax application for the taxable account and direct contributions for IRAs.
Frequently Asked Questions
When is a taxable brokerage account better than an IRA?
A taxable account may be better when your retirement tax rate will be similar to or higher than your current capital gains rate, when you need access before 59 1/2, when you have already maxed out IRA and 401(k) contributions, or when you want to use tax-loss harvesting.
How are taxable investment accounts and traditional IRAs taxed differently?
In a taxable account, you pay capital gains tax only on profit when you sell, and qualified dividends get the lower capital gains rate. In a traditional IRA, you get a tax deduction on contributions but pay ordinary income tax on the entire withdrawal amount.
Does tax-deferred growth in an IRA always beat a taxable account?
Not always. If your taxable account gains qualify for the 15% long-term capital gains rate and you use tax-loss harvesting, the after-tax result can be similar or better, especially if your retirement income tax rate is high.
What are the liquidity differences between a taxable account and an IRA?
Taxable accounts offer full liquidity with no age restrictions or penalties. Traditional IRAs impose a 10% early withdrawal penalty before age 59 1/2. Roth IRAs allow tax-free withdrawal of contributions at any time but earnings may be penalized.