Enter Values

%
Enter as percentage (e.g., 8 for 8%)
%
Flat tax rate for annual accrual regime
%
Long-term capital gains tax rate
1.0 = new investment; < 1.0 = unrealized gains exist
%
Ordinary income / interest tax rate
%
Qualified dividend tax rate
%
Capital gains tax rate for blended regime
%
Portion of return from interest income
%
Portion of return from dividends
%
Auto-calculated: 100% - interest - dividends
years
Number of years invested
$
Starting investment amount
Tax Regime Formulas
Annual: rAT = rPT × (1 - t)
Deferred: FV = V × [(1+r)n(1-t) + tB]
Blended: rAT = rPT × (1 - piti - pdtd - pcgtcg)
Ryan O'Connell, CFA
Calculator by Ryan O'Connell, CFA

After-Tax Results

After-Tax Return 5.60% 30.00% Tax Drag
Tax Drag 30.00%
Tax Drag ($) $168,739
Effective Tax Rate 46.10%
Pre-Tax Terminal $466,096
After-Tax Terminal $297,357
Wealth Lost to Taxes $168,739

Formula Breakdown

Annual Accrual: rAT = rPT × (1 - t)
Model Assumptions
  • Returns are constant each year (no compounding of random returns)
  • Tax rates are constant over the investment horizon
  • Annual Accrual: taxes reduce the effective annual return each year
  • Deferred CG: all gains are realized and taxed at the end of the horizon
  • Does not model tax-loss harvesting, asset location, or estate taxes

For educational purposes. Not financial advice. Market conventions simplified.

Tax Drag Interpretation

Tax Drag Rating Implication
< 20% Low Tax-efficient structure
20% - 40% Moderate Typical for balanced portfolios
> 40% High Consider tax optimization strategies

Understanding After-Tax Returns

What is Tax Drag?

Tax drag is the reduction in investment returns caused by taxes. While investors focus on pre-tax returns, the actual wealth they accumulate depends on after-tax performance. Over long horizons, the effective tax rate on accumulated wealth can significantly exceed the statutory tax rate due to the compounding effect of annual tax payments.

Three Tax Regimes

Annual Accrual

All gains taxed each year (interest, short-term CG). Reduces effective compounding rate. Simplest but highest tax drag.

Deferred Capital Gains

Taxes paid only at sale. Full pre-tax return compounds each year. Lower effective tax rate over long horizons.

Why Deferral Matters

Over a 20-year horizon with an 8% pre-tax return, annual accrual taxation at 30% produces a 5.6% after-tax return, while deferred capital gains at 20% produces approximately 7.08%. The effective tax rate on wealth under annual accrual (46.1%) far exceeds the statutory rate (30%) because taxes reduce the base that compounds each year.

Key Insight: Use the Annualized Return Calculator to determine your pre-tax return, then feed that result here to assess the tax impact.

Frequently Asked Questions

Tax drag is the reduction in investment returns caused by taxes. It measures the percentage difference between pre-tax and after-tax returns. For example, an 8% pre-tax return with a 30% tax rate produces a 5.6% after-tax return, resulting in a 30% tax drag on returns. Over long horizons, the effective tax rate on accumulated wealth can exceed the statutory tax rate due to the compounding effect of annual tax payments.

The calculation depends on your tax regime. For annual accrual (interest, short-term gains), the after-tax return equals the pre-tax return multiplied by (1 minus the tax rate). For deferred capital gains, the formula accounts for tax deferral benefits: FV = V × [(1+r)n × (1-t) + t × B], where B is the cost basis ratio. For blended portfolios, weight each income type by its proportion and tax rate.

Annual accrual taxation applies to interest income and short-term capital gains, where taxes are paid each year on realized gains. This reduces the effective compounding rate. Deferred capital gains taxation applies to unrealized appreciation, where taxes are only paid when the investment is sold. Deferral allows the full pre-tax return to compound, resulting in significantly higher after-tax terminal wealth over long horizons.

The blended regime recognizes that portfolio returns come from multiple sources: interest income, dividends, and capital gains, each taxed at different rates. The after-tax return equals the pre-tax return multiplied by (1 minus the weighted average of tax rates), where weights are the proportion of return from each income type. For example, if 30% of returns come from interest taxed at 37%, 20% from dividends taxed at 20%, and 50% from capital gains taxed at 20%, the blended tax rate is 25.1%.

Tax deferral allows the full pre-tax return to compound each year, rather than a reduced after-tax return. Over a 20-year horizon with an 8% pre-tax return and 20% capital gains tax rate, deferred taxation produces an after-tax return of approximately 7.08%, compared to 5.6% under annual accrual at 30%. The longer the investment horizon, the greater the benefit of deferral, which is why tax-efficient strategies like buy-and-hold and index investing are favored for long-term investors.

The cost basis ratio (B) equals the original cost basis divided by the current market value. A ratio of 1.0 means the investment is new (no unrealized gains). A ratio below 1.0 means there are existing unrealized gains that will be taxed upon sale. A lower cost basis ratio increases the tax liability at liquidation, reducing the after-tax terminal value. For example, an investment with B = 0.50 has 50% unrealized gains that will be taxed at the capital gains rate when sold.
Disclaimer

This calculator is for educational purposes only and uses simplified tax models. Actual tax situations involve additional factors like state taxes, AMT, wash sale rules, and tax-loss harvesting. Consult a qualified tax professional for personalized tax planning advice. This tool should not be used for tax filing or investment decisions.

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Course by Ryan O'Connell, CFA, FRM

Portfolio Analytics & Risk Management Course

Master portfolio theory and risk management from fundamentals to advanced analytics. Covers modern portfolio theory, risk metrics, performance evaluation, and factor models.

  • Tax-efficient investing and after-tax return analysis
  • Modern Portfolio Theory and efficient frontier construction
  • Risk metrics: VaR, CVaR, drawdown analysis
  • Hands-on exercises with real portfolio data
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