Tax-Loss Harvesting Calculator 2026
Enter your gains and harvestable losses to see your tax savings instantly — then check the wash-sale rule and read exactly how the netting works.
The wash-sale rule disallows a loss if you buy the same or a substantially identical security within 30 days before or after the sale. Enter both dates to check.
Understand your result
Losses are netted by holding period first: short-term losses offset short-term gains (taxed at your ordinary rate), and long-term losses offset long-term gains (taxed at 0%, 15%, or 20%). Because short-term gains are taxed more heavily, using losses to wipe them out usually saves the most tax. Leftover losses of one type then offset gains of the other type.
If you still have a net loss after offsetting all gains, you can deduct up to $3,000 against ordinary income ($1,500 if married filing separately), and carry the rest forward indefinitely. The catch is the wash-sale rule — rebuying too soon disallows the loss — so many investors swap into a similar (not identical) fund to stay invested while banking the loss.
You have $8,000 of long-term gains and sell a fund with a $6,000 long-term loss (24% ordinary bracket, 15% LT rate):
- The $6,000 loss offsets $6,000 of your gains → only $2,000 of gain is taxed
- Tax without harvesting: $8,000 × 15% = $1,200
- Tax after harvesting: $2,000 × 15% = $300
- You save $900 this year — and if you swap into a similar fund after 31 days, you stay invested
- Rebuying the same fund within 30 days — the wash-sale rule disallows the loss and resets your basis.
- Harvesting in an IRA or 401(k) — it does nothing; only taxable accounts count.
- Forgetting that buying in a spouse's account or IRA can also trigger a wash sale.
- Chasing tiny losses and racking up trading costs or drifting from your target allocation.
- Overlooking that reinvested dividends within the window can count as a repurchase.