See how much selling an investment at a loss could save you. Enter your cost basis, current value, other capital gains to offset, and your tax rate to get the realized loss, this year's tax savings, and any loss carried forward.
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Results
Calculated
Capital Loss Realized
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Cost basis minus current value
Estimated Tax Savings
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Loss used this year × tax rate
Capital Gains Offset
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Portion of the loss applied against your gains
Loss Carried Forward
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After gains offset and the $3,000/yr ordinary-income limit
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How to use this calculator
Enter the cost basis (what you paid for the investment) and its current market value. If the current value is lower, you have an unrealized capital loss. Add any other capital gains you want to offset this year and your applicable tax rate, then click Calculate to see the realized loss, the estimated tax savings, and any amount carried forward. Click Clear to reset all fields.
The formula
Tax-loss harvesting follows a standard sequence defined by U.S. tax rules:
Capital Loss = Cost Basis − Current Market Value (zero if the investment gained value).
That loss is first applied against capital gains you realized elsewhere. Any loss left over can offset up to $3,000 of ordinary income per year (the IRS annual limit; $1,500 if married filing separately). Whatever remains after both offsets carries forward to future tax years indefinitely. Estimated tax savings equal the loss actually used this year multiplied by your tax rate:
Tax Savings = (Loss Used This Year) × (Tax Rate)
Interpreting the results
"Capital Loss Realized" is the full loss from the sale. "Estimated Tax Savings" is what that loss is worth this year at your tax rate. "Capital Gains Offset" shows how much of the loss cancelled out other gains. "Loss Carried Forward" is the leftover loss — after gains offset and the $3,000 ordinary-income cap — available to use in future years.
Frequently Asked Questions
What is tax-loss harvesting?
Tax-loss harvesting is selling an investment for less than you paid for it (cost basis minus current value) to realize a capital loss on purpose. That loss can offset capital gains you realized elsewhere, and up to $3,000 per year of any leftover loss can offset ordinary income, reducing your tax bill.
How much loss can offset ordinary income?
After a harvested loss is used to offset capital gains, the IRS allows up to $3,000 per year ($1,500 if married filing separately) of the remaining loss to offset ordinary income. Any loss beyond that annual limit is not lost — it carries forward to future tax years indefinitely.
What is the wash-sale rule?
The wash-sale rule disallows the tax loss if you buy the same security, or one the IRS considers substantially identical, within 30 days before or after the sale. To keep the loss deductible while staying invested, many investors swap into a similar but not identical fund during that window.
How is the tax savings figure calculated?
Tax savings equals the loss actually used this year (the portion offsetting gains, plus up to $3,000 offsetting ordinary income) multiplied by your applicable tax rate. Loss carried forward to future years produces additional savings later, when it is finally used.
Practical Guide for Tax Loss Harvesting Calculator (Tax Loss Harvest) - Finance Calculator
Tax Loss Harvesting Calculator (Tax Loss Harvest) - Finance Calculator is most useful when the inputs reflect the situation you are actually planning around, not a best-case estimate. Treat the result as a decision aid: it gives you a structured way to compare assumptions, spot outliers, and decide what to verify next. For Finance work, the most important review lens is cash flow, timing, rates, risk tolerance, and the reliability of each assumption.
Start with a baseline run using values you can defend. Then change one assumption at a time and watch which output moves the most. If one input dominates the result, spend your verification time there first. If several inputs have similar influence, use a conservative scenario and an optimistic scenario to create a practical range instead of relying on a single exact number.
Before acting on the result, compare the result with bank statements, invoices, amortization schedules, or accounting exports before making a commitment. This is especially important when the calculator supports a purchase, project plan, performance target, or operational decision. The calculator can make the math consistent, but the quality of the conclusion still depends on current data, clear units, and assumptions that match your real constraints.
When the output looks surprising, slow down and inspect each input in order. A small change in one high-leverage field can move the final number more than several low-leverage fields combined. For Tax Loss Harvesting Calculator (Tax Loss Harvest) - Finance Calculator, that means you should first confirm the value with the greatest scale, then confirm the value with the greatest uncertainty, then rerun the calculator with conservative and optimistic assumptions. This sequence turns the calculator from a single answer into a practical decision range.
Review Checklist
Confirm every input uses the unit and time period requested by the calculator.
Run a low, expected, and high scenario so the answer has a useful range.
Check whether rounding or a missing decimal place changes the decision.
Update the calculation monthly or whenever income, rates, expenses, or balances change materially.