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Tax-Loss Harvesting Calculator

Enter your capital gains, harvested losses, and tax bracket to see exactly how much tax you save, what carries forward, and how those savings compound over time.

Your gains this year
Short-term capital gains $5,000
$
Long-term capital gains $10,000
$
Losses to harvest
Harvested loss amount $8,000
$
Prior-year carryforward losses $0
$
Your tax situation
Filing status
Ordinary income tax bracket
Long-term CGT rate
Compounding assumption
Annual return on savings 7%
Without harvesting
$0
Total tax owed on gains
With harvesting
$0
Total tax owed on gains
Tax saved this year
$0
Loss carried forward
$0
Savings value in 20 yrs
$0
How the harvesting applies
Short-term gains$0
Long-term gains$0
Prior carryforward applied$0
New harvested loss applied$0
Remaining taxable gains$0
Income offset used (up to $3K limit)$0
New carryforward to future years$0
Total tax saved$0
Compounding value of tax savings over time

Why losses offset gains first: The IRS requires capital losses to offset capital gains before they can reduce ordinary income. Short-term losses first offset short-term gains; long-term losses first offset long-term gains. Excess losses in either category then offset the other. After all gains are eliminated, up to $3,000 ($1,500 married filing separately) of remaining net losses can reduce ordinary income.

This calculator provides estimates for educational purposes only. It does not account for state taxes, the net investment income tax (NIIT), AMT, or the specific ordering rules in complex multi-lot situations. Actual tax savings depend on your full tax situation. Consult a qualified tax professional before implementing tax-loss harvesting strategies. Not financial or tax advice.

How the tax-loss harvesting calculator works

This calculator models the tax impact of harvesting investment losses against your capital gains. Enter your short-term and long-term gains for the year, the amount of losses you plan to harvest, any carryforward losses from prior years, and your tax bracket. The calculator applies losses in the correct IRS order — gains first, then up to $3,000 against ordinary income — and shows the remaining carryforward balance.

The compounding chart shows the long-term value of reinvesting your tax savings. A $1,500 tax saving today, reinvested and compounding at 7% annually, is worth approximately $5,800 in 20 years. This is the actual return from tax-loss harvesting — not just the immediate reduction, but the compounded value of capital retained.

How to use this calculator

Read the full guide on how tax-loss harvesting works including the wash sale rule, replacement fund strategies, and the DCA investor playbook.