Tax-loss harvesting turns investment losses into real tax savings by selling losing positions to offset capital gains taxes. This calculator shows your exact tax savings, net after-tax proceeds, and reminds you about the 30-day wash sale rule to avoid disallowed losses.
Loss Details
Cost basis minus current value
Used for short-term gains; long-term uses 15% or 20%
Tax Savings Summary
Carry Forward
Wash Sale Warning
Do not repurchase the same or substantially identical security within 30 days before or after the sale, or your loss will be disallowed by the IRS wash sale rule. Consider replacing with a similar but not identical ETF.
How to Use the Tax-Loss Harvesting Calculator
Tax-loss harvesting is one of the most effective tax management strategies available to investors. This calculator shows you exactly how much you save in taxes and helps you understand the wash sale rule before you execute trades.
Step 1: Enter Your Loss Amount and Type
Enter the total capital loss you are considering harvesting — this is your cost basis minus the current value of the losing position. Select whether it is a short-term loss (held less than 1 year) or long-term loss (held more than 1 year). Short-term losses are generally more valuable because they can offset short-term gains taxed at higher ordinary income rates.
Step 2: Enter the Gains You Want to Offset
Enter the capital gains you have already realized this year (or plan to realize) that you want to offset with the harvested losses. Select whether those gains are short-term or long-term — matching loss type to gain type provides the most efficient offset, though any loss can offset any type of gain.
Step 3: Review Tax Savings
The calculator shows your tax savings, any excess loss available to carry forward, and the amount you can deduct against ordinary income (up to $3,000 per year) if losses exceed gains. Any remaining carry-forward losses can offset future gains in subsequent years.
Avoiding the Wash Sale Rule
The most common mistake in tax-loss harvesting is violating the wash sale rule by repurchasing the same security too quickly. Wait at least 31 days before repurchasing, or buy a similar but not identical replacement — for example, replace VTI (Vanguard Total Stock Market) with ITOT (iShares Core S&P Total US Stock Market), which tracks a different index but has high correlation.
Frequently Asked Questions
Is this tax-loss harvesting calculator free?
Yes, completely free with no signup required. All calculations run in your browser.
Is my data private?
Absolutely. Everything runs client-side in your browser. No data is transmitted or stored.
What is tax-loss harvesting?
Tax-loss harvesting is selling investments at a loss to offset capital gains taxes on other investments. For example, if you have a $10,000 gain from selling appreciated stock but also have $6,000 in unrealized losses in another holding, selling the losing position reduces your taxable gain to $4,000, saving you the tax on $6,000 of gains.
What is the wash sale rule?
The IRS wash sale rule disallows the tax loss if you buy the same or 'substantially identical' security within 30 days before or after the sale. For example, if you sell VTI at a loss and repurchase VTI within 30 days, the loss is disallowed. You can avoid this by waiting 31 days or buying a similar but not identical ETF (e.g., selling VTI and buying ITOT, which tracks a different but correlated index).
What are the capital gains tax rates?
Short-term capital gains (assets held less than 1 year) are taxed at your ordinary income rate, which can be up to 37% for high earners. Long-term capital gains (held more than 1 year) are taxed at 0%, 15%, or 20% depending on your income. Harvesting short-term losses against short-term gains provides the greatest benefit since those are taxed at higher rates.
Can I deduct losses beyond my capital gains?
Yes. If your capital losses exceed your capital gains in a given year, you can deduct up to $3,000 of net losses against ordinary income per year. Any remaining losses carry forward to future tax years indefinitely until fully used.