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Tax Loss Harvesting Calculator

Calculate how much you can save in taxes by harvesting investment losses. Offset capital gains with realized losses, carry forward unused losses, and see the long-term impact on your portfolio.

💰 Your Capital Gains & Losses

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How the Tax Loss Harvesting Calculator Works

Tax loss harvesting is a strategy where you sell investments that have declined in value to realize capital losses, which can offset capital gains and reduce your tax bill. This calculator shows you exactly how much you can save.

📉 Realize capital losses
⚖️ Offset capital gains
💰 Reduce tax liability
📅 Carry forward unused losses

How Losses Offset Gains

Capital losses first offset capital gains of the same type (short-term losses offset short-term gains; long-term losses offset long-term gains). Any remaining losses can offset gains of the opposite type. If you still have leftover losses after offsetting all gains, you can deduct up to $3,000 per year ($1,500 if married filing separately) from ordinary income and carry forward the rest indefinitely.

Long-Term Capital Gains Tax Rates

Long-term capital gains are taxed at preferential rates based on your taxable income:

Calculator Features

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Gain vs Loss Offset

See exactly how your realized losses offset both short-term and long-term capital gains to minimize taxes.

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Instant Tax Savings

Get a clear breakdown of taxes owed with and without harvesting, plus your total savings this year.

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Multi-Year Projection

See how unused losses carry forward year after year, offsetting up to $3,000 of ordinary income annually.

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Accurate Tax Rates

Uses the correct long-term capital gains tax brackets plus the 3.8% Net Investment Income Tax when applicable.

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Mobile Optimized

Works perfectly on phones, tablets, and desktops. All calculations run privately in your browser.

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Completely Free

No registration, no hidden fees, no data collection. Professional-grade tax analysis at no cost.

Formulas Used

Net Capital Gain/Loss

realized_gains = ST_gains + LT_gains
Total realized capital gains
realized_losses = ST_losses + LT_losses
Total realized capital losses
net_capital_gain = max(0, realized_gains − realized_losses)
If gains exceed losses, you have a net gain
net_capital_loss = max(0, realized_losses − realized_gains)
If losses exceed gains, you have a net loss

Tax Without Harvesting

tax_without = ST_gains × ST_rate + LT_gains × LT_rate
ST_rate
Marginal income tax rate (ordinary income rate)
LT_rate
Long-term capital gains rate (0%, 15%, or 20%) + possible 3.8% NIIT

Tax With Harvesting

Losses first offset gains of the same type, then the opposite type:

remaining_loss = max(0, remaining ST_loss + remaining LT_loss)
After same-type offset, remaining losses offset opposite-type gains

If net losses exist after offsetting all gains, up to $3,000 can offset ordinary income:

ordinary_deduction = min(net_capital_loss, $3,000)
Deduct from ordinary income at your marginal tax rate

Multi-Year Carryover Projection

Year N: ordinary deduction = min(carryover, $3,000)
Each year, up to $3,000 offsets ordinary income until carryover is exhausted

Tips for Tax Loss Harvesting

📉 Harvest Losses Regularly

Review your portfolio at least once a year for positions with unrealized losses. December is a popular time for tax-loss harvesting, but you can do it any time.

⚠️ Watch the Wash Sale Rule

If you sell a security at a loss and buy a "substantially identical" security within 30 days before or after the sale, the loss is disallowed. Wait at least 31 days or buy a different security.

🔄 Reinvent, Don't Reinvest

After harvesting a loss, reinvest in a similar but not identical holding (e.g., sell S&P 500 ETF, buy total market ETF) to maintain market exposure while avoiding wash sale rules.

📊 Prioritize High-Rate Offsets

Short-term losses are best used to offset short-term gains (taxed at higher ordinary income rates) first. Long-term losses offset long-term gains (taxed at lower rates).

Frequently Asked Questions (FAQ)

What is tax loss harvesting?

Tax loss harvesting is a strategy where you sell losing investments to realize capital losses, which can offset capital gains taxes. By intentionally realizing losses, you reduce your taxable capital gains and potentially lower your tax bill. Any unused losses can be carried forward to future years.

What is the wash sale rule?

The wash sale rule disallows a capital loss if you buy a "substantially identical" security within 30 days before or after the sale. If the IRS determines a wash sale occurred, the loss is added to the cost basis of the new shares instead of being recognized. To avoid this, wait at least 31 days before repurchasing, or buy a different but similar investment.

How much can I deduct from ordinary income?

You can deduct up to $3,000 per year ($1,500 if married filing separately) of net capital losses against ordinary income. Any remaining losses can be carried forward to future years indefinitely until fully used.

Can I carry forward unused capital losses?

Yes, unused capital losses can be carried forward indefinitely until fully utilized. Each year, you can use up to $3,000 of carried-forward losses to offset ordinary income ($1,500 if married filing separately), and any remaining continues to carry forward. Losses never expire — they stay with you until used or until death.

Should I always harvest losses?

Not necessarily. Consider the wash sale rule, transaction costs, and your overall investment strategy. Tax loss harvesting is most beneficial when you have capital gains to offset or when you can use the $3,000 ordinary income deduction. If harvesting would cause you to miss a market rebound or incur significant trading fees, it may not be worth it.

Does tax loss harvesting affect my investment strategy?

It shouldn't. Tax loss harvesting is a tax optimization strategy, not an investment strategy. After harvesting a loss, you should reinvest in a similar but not identical holding to maintain your desired asset allocation and market exposure. The goal is to reduce taxes without significantly altering your long-term investment plan.

About This Tax Loss Harvesting Calculator

Our Tax Loss Harvesting Calculator helps investors understand the tax savings potential of harvesting investment losses. Whether you're considering selling underperforming positions or want to maximize your after-tax returns, this tool provides clear, actionable numbers.

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Accurate Tax Modeling

Full short-term and long-term gain/loss offset logic with correct long-term capital gains tax brackets and NIIT calculations.

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5-Year Projection

See how carried-forward losses impact your taxes over the next five years with a clear year-by-year table.

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100% Private

All calculations run in your browser. No data is sent to or stored on any server. Your financial information stays with you.

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Free to Use

Professional tax-loss harvesting analysis at no cost. No registration, no credit card, no limits.

⚠️ Important Disclaimer: This calculator is for estimation and educational purposes only. Tax laws are complex and subject to change. The wash sale rule, alternative minimum tax (AMT), and other tax provisions may affect your specific situation. For personalized tax advice, consult a qualified tax professional or CPA.