Tax-Loss Harvesting Calculator

About the Tax-Loss Harvesting Calculator

The Tax-Loss Harvesting Calculator helps you estimate the tax savings from strategically selling investments at a loss to offset capital gains and reduce your tax bill. This powerful strategy, used by individual investors and professional wealth managers alike, can save thousands of dollars annually when executed properly.

Tax-loss harvesting works by realizing paper losses, using those losses to offset realized capital gains dollar for dollar, and deducting up to $3,000 of excess losses against ordinary income each year. Any remaining losses carry forward to future tax years indefinitely. The key constraint is the wash sale rule, which disallows the loss if you repurchase a substantially identical security within 30 days.

This calculator factors in your harvested losses, existing capital gains, marginal tax rate, transaction costs, and the annual deduction limit to show your net tax benefit. It also estimates the carry-forward amount if your losses exceed what can be used in the current year.

When This Page Helps

Tax-loss harvesting is one of the few legitimate strategies to immediately reduce your tax bill without changing your long-term investment strategy. By replacing a losing position with a similar (but not identical) investment, you maintain market exposure while booking a tax loss. This calculator quantifies the benefit so you can decide whether the savings justify the transaction costs.

How to Use the Inputs

1. Enter the total amount of capital losses you plan to harvest (sell at a loss).
2. Enter any capital gains you have already realized this year.
3. Enter your marginal federal tax rate (income tax bracket).
4. Enter your state tax rate if applicable.
5. Enter estimated transaction costs (commissions, fees, bid-ask spreads).
6. View the tax savings, net benefit after costs, and any loss carry-forward.
7. Consider the wash sale rule: do not repurchase the same security within 30 days.

Example Calculation

Tips & Best Practices

• Harvest losses throughout the year, not just in December; opportunities appear during market pullbacks.
• Replace the sold holding with a similar but not substantially identical investment to maintain market exposure.
• Avoid triggering the wash sale rule by waiting 31+ days before repurchasing the same security.
• Consider using ETFs to swap between similar but distinct index funds (e.g., S&P 500 to total market).
• Track all carry-forward losses to use them in future high-gain years.
• Short-term losses offset short-term gains first, which are taxed at higher rates.
• Pair tax-loss harvesting with tax-gain harvesting in low-income years for a complete tax strategy.

How Tax-Loss Harvesting Creates Value

The primary value of tax-loss harvesting comes from realizing losses now and potentially deferring some tax liability into future years. The benefit depends on your capital gains, marginal tax rate, transaction costs, replacement holdings, and how long the deferred tax amount stays invested.

The Wash Sale Rule in Detail

The wash sale window runs both before and after the sale date, creating a 61-day period that can disallow the deduction if you buy substantially identical securities too close to the sale. If the wash sale rule applies, the disallowed loss is generally added to the basis of the replacement position rather than disappearing permanently.

Building a Systematic Harvesting Strategy

The most effective approach is to monitor your portfolio regularly for harvesting opportunities rather than waiting until year-end. Market corrections and individual security pullbacks create harvesting windows throughout the year, but the tax result still depends on recordkeeping and replacement-security choices.

Frequently Asked Questions

• What is tax-loss harvesting?

  Tax-loss harvesting is the strategy of selling investments at a loss to generate capital losses that offset capital gains and up to $3,000 of ordinary income per year on your tax return. The goal is to reduce your current tax bill while maintaining a similar investment portfolio by purchasing a non-identical replacement security.

• What is the wash sale rule?

  The wash sale rule prevents you from claiming a tax loss if you buy a substantially identical security within 30 days before or after the sale. If triggered, the disallowed loss is added to the cost basis of the replacement shares rather than being lost entirely. The rule applies across all your accounts, including IRAs.

• How much can I deduct against ordinary income?

  After offsetting all capital gains, you can deduct up to $3,000 per year ($1,500 if married filing separately) of remaining net capital losses against ordinary income. Any excess losses carry forward indefinitely to future tax years. There is no limit on using losses to offset capital gains.

• Do losses carry forward to future years?

  Yes. Any capital losses that exceed your capital gains plus the $3,000 ordinary income offset carry forward to the next tax year. They retain their character as short-term or long-term losses. There is no expiration on carry-forward losses; they persist until fully used.

• Is tax-loss harvesting worth it for small losses?

  It depends on your transaction costs and the complexity involved. For losses under a few hundred dollars, the administrative effort and potential trading costs may not justify the tax savings. For losses of $1,000 or more, the tax benefit usually outweighs the costs, especially if trading is commission-free.

• Can I harvest losses in retirement accounts?

  No. Tax-loss harvesting only applies to taxable investment accounts. Gains and losses in IRAs, 401(k)s, and other tax-deferred accounts are not reported for tax purposes until distributions are taken. There is no tax benefit to selling at a loss inside a retirement account.

• How does tax-loss harvesting affect my cost basis?

  When you sell at a loss and buy a replacement investment, the new investment has a lower cost basis than the original. This means you may pay more capital gains tax in the future when you sell the replacement. Tax-loss harvesting defers taxes rather than eliminating them permanently, though the time value of deferred taxes is still beneficial.

• What counts as a substantially identical security?

  The IRS has not precisely defined this term, but generally, shares of the same company, options on the same stock, and very similar mutual funds tracking the same index are considered substantially identical. Different index funds from different providers (e.g., an S&P 500 ETF vs. a total market ETF) are generally considered distinct enough to avoid the wash sale rule.