Decision Summary
Total tax saved
$2,250.00
Harvesting $15,000 in losses offsets $15,000 in gains and $0 in ordinary income.
Tax
Tax-Loss Harvesting Calculator
Estimate the tax savings from harvesting investment losses against capital gains and income.
Scenario Comparison
The main answer and the most important supporting outputs in one glance.
Total tax saved
$2,250.00
Gains offset by losses
$15,000.00
Ordinary income deduction
$0.00
Losses carried forward
$0.00
Key Metrics
Gains offset by losses
$15,000.00
Ordinary income deduction
$0.00
Losses carried forward
$0.00
Effective harvest benefit
15.00%
How to use it
- Enter unrealized losses by position, your marginal tax rate, capital gains to offset, the wash-sale replacement you plan to use, and any state tax rate. Harvesting only works if you have gains to offset or can use the $3,000 annual ordinary income deduction.
- Read estimated tax savings, net benefit after transaction costs, and whether the loss is short-term or long-term. Short-term losses offset short-term gains first, which are taxed at higher ordinary rates, making them more valuable per dollar harvested.
- If the tax savings are under a few hundred dollars and you need to buy a non-identical replacement fund to avoid the wash-sale rule, the tracking burden and slight tracking error may not be worth it. Harvesting is most powerful with large concentrated losses.
- Sell the losing position, immediately buy a similar but not substantially identical fund, and wait 31 days before repurchasing the original if you prefer it. Log the transaction for tax filing and carry forward unused losses. Use the tax bracket calculator to confirm your marginal rate.
- Re-run in October-December for year-end tax planning and after any sharp market decline. Track cumulative harvested losses, losses used versus carried forward, and the net tax benefit realized.
AI Integrations
Contract, discovery endpoints, and developer notes for agent use.
Always available for agents
AI Integrations
Contract, discovery endpoints, and developer notes for agent use.
Tool contract JSON
https://aifinhub.io/contracts/tax-loss-harvesting-calculator.jsonStable input and output contract for this exact tool.
Human review
People can use the browser page to sense-check outputs and charts, but agents should still execute against the contract and discovery endpoints.
- /agent-tools.json - machine-readable tool index.
- /llms.txt - human-readable model discovery guide.
- /.well-known/webmcp.json - WebMCP capabilities manifest.
- /.well-known/ai-plugin.json - plugin-style discovery manifest.
{
"tool": "tax_loss_harvesting",
"unrealized_losses": 18000,
"capital_gains_this_year": 12000,
"ordinary_income_offset": 3000,
"capital_gains_tax_rate_percent": 15,
"income_tax_rate_percent": 24
} Expand developer notes
Agent playbook
- Resolve Tax-Loss Harvesting Calculator from /agent-tools.json and open its contract before execution.
- Validate inputs against the contract schema instead of scraping labels from the page UI.
- Open the browser page only when a person wants to review charts, assumptions, or related tools.
Agent FAQ
Should ChatGPT, Claude, or another agent click through the UI?
No. Start with /agent-tools.json, then follow the tool's contract URL. The page UI is for human review, not parameter discovery.
When do tools show Quick and Advanced?
Every tool opens in Quick Start first. Advanced Controls keeps the same scenario, reveals more assumptions or diagnostics, and every tool keeps AI integrations inline below the instructions.
When should an agent still open the browser page?
Open it when a human wants to sense-check the output, review the chart, or keep exploring related tools after the calculation finishes.
Questions people usually ask
What is tax-loss harvesting?
It is the practice of selling investments at a loss to offset capital gains taxes, then reinvesting in a similar (but not substantially identical) asset to maintain market exposure. The harvested loss reduces your current tax bill while your portfolio stays invested.
How much can tax-loss harvesting save?
It depends on your tax bracket and the size of your losses. At a 24% federal bracket, harvesting $10,000 in losses saves $2,400 in taxes (more if offsetting short-term gains taxed at ordinary rates). You can also deduct $3,000/year against ordinary income and carry forward unlimited losses.
What is the wash sale rule?
If you buy a substantially identical security within 30 days before or after selling at a loss, the IRS disallows the loss. You must wait 31 days or buy a different-but-similar fund (e.g., sell an S&P 500 fund, buy a total market fund). The tool flags wash sale windows.
When should I use this vs doing harvesting manually?
Use this to quantify the tax benefit before executing trades. It models the savings from harvesting specific lots, accounts for your bracket, and checks whether the trade is worth the effort and transaction costs.
Is my data stored?
No. All calculations happen in your browser. Nothing is stored or transmitted.
Continue With Related Tools
Side Hustle Tax Calculator
Estimate side-hustle tax impact and set monthly/quarterly reserves with clear non-advice planning disclosures.
Gig Worker Quarterly Tax Set-Aside Planner
Estimate quarterly tax reserves for freelance and gig income with safe-harbor aware monthly and quarterly targets.
Tax Bracket Calculator
Estimate 2025 US federal tax by filing status with marginal vs effective tax rate and bracket-by-bracket tax breakdown.
Paycheck Take-Home Calculator
Estimate your net take-home pay after federal income tax, state income tax, FICA, 401k, and health insurance deductions. See your effective tax rate and annual net income.