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Tax-loss harvesting calculator:
how much can you save?

Enter your portfolio size, federal bracket, and state. The calculator estimates your annual tax savings based on 2026 federal capital-gains brackets, the Net Investment Income Tax, and your state’s top-marginal rate.

$500,000
$50k$5M+
12%
5%30%

In a typical year with normal market volatility, most diversified portfolios have 8–15% sitting in unrealized losses at any given moment, even when the overall portfolio is up. Brokerages don’t flag these.

13.3%
Estimated annual tax savings
$19,260
Over 10 years: $192,600
Federal capital gains (15%)$9,000
Net investment income tax (3.8%)$2,280
State (13.3%)$7,980
Total effective rate32.1%
Find these losses in your accounts →

Estimate based on harvesting unrealized losses to offset realized capital gains. Assumes you have realized gains to offset (most diversified portfolios do, through rebalancing). Without gains, savings are capped at $3,000/year against ordinary income with the rest carrying forward indefinitely.

How tax-loss harvesting saves you money

1

You realize a paper loss

Sell a position trading below your cost basis. The brokerage records a realized capital loss for the tax year — even though, on paper, your portfolio value is unchanged once you reinvest.

2

The loss offsets your gains

Realized losses offset realized capital gains dollar-for-dollar. Long-term losses match long-term gains first, short-term against short-term. Excess losses up to $3,000/year offset ordinary income; the rest carries forward.

3

You stay invested

Immediately reinvest in a similar (but not substantially identical) security to maintain market exposure. Buy back the original after 30 days when the wash-sale window closes.

Why brokerages miss most of these opportunities

Your broker only sees its own accounts. If you hold positions at E*TRADE, Fidelity, Schwab, Robinhood, or a 401(k), no single platform can see your full portfolio — and none can flag wash sales that happen across accounts. The IRS still expects you to catch them. TaxHarvest connects every account into one view, surfaces lot-level harvesting opportunities your broker can’t see, and tracks 30-day wash-sale windows across every linked account.

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Frequently asked questions

How accurate is this tax-loss harvesting calculator?
The estimate uses 2026 federal long-term capital-gains brackets, the Net Investment Income Tax surcharge (3.8% above $200k single / $250k MFJ), and current state top-marginal cap-gains rates. It assumes you have realized capital gains to offset — which most diversified investors do through rebalancing or selling winners. Results are typically within 5-15% of actual savings for someone with the inputs you provide.
What if I don't have any realized capital gains this year?
Without realized gains, harvested losses still reduce your tax bill — but more slowly. The first $3,000 of net losses each year offsets ordinary income (a $1,110 federal savings in the 37% bracket). The remaining losses carry forward indefinitely, ready to offset gains in future years. The calculator shows the higher number (with gains to offset) because that's the most common case for portfolios over $250k.
Why does the calculator ask about my state?
Most US states tax capital gains as ordinary income, with rates ranging from 0% (Florida, Texas, Nevada, Washington under $250k cap gains) to 13.3% (California). State tax can be the largest piece of your effective rate — a $20,000 harvested loss saves $5,640 in California vs $3,000 in Texas at the same federal bracket.
Can I tax-loss harvest across multiple brokerages?
You can — but only if you actively track wash sales across all of them. Brokerages only see their own accounts. If you sell at a loss in E*TRADE and rebuy in Fidelity within 30 days, neither broker will catch it, but the IRS still expects you to. This is exactly what TaxHarvest automates: connecting every account into one view to flag cross-broker wash-sale risks before you trade.
How much do most TaxHarvest customers actually save?
Most customers save between $10,000 and $50,000 per year. Investors with portfolios over $1M and high marginal tax rates often save $30,000+. The biggest variable is whether harvesting happens systematically year-round (more savings) or only during a December review (fewer opportunities, since many losses recover before year-end).
Does tax-loss harvesting work in retirement accounts?
No. Tax-loss harvesting only applies to taxable brokerage accounts. Losses inside an IRA, 401(k), or 529 cannot be claimed because the gains in those accounts are also tax-deferred or tax-free. The calculator assumes you're entering only your taxable portfolio size.
What is the wash sale rule and does the calculator account for it?
The wash sale rule disallows a tax loss if you buy the same or substantially identical security within 30 days before or after selling at a loss. The calculator assumes the loss is successfully realized (no wash sale violations) — which is what TaxHarvest enforces by suggesting correlated replacement securities and tracking the 30-day rebuy window automatically.

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