Tested tool guide
Tested browser tools
Checked August 16, 2026
What Tax-Loss Harvesting Calculator does, with a checked example
Selling a losing investment is only worth it if you know what the loss is actually worth, and most people guess wrong: the loss does not save you its full value, and the wash sale rule can silently erase it. The tool nets your realized gains and losses for the year, applies the $3,000 annual cap on deductions against ordinary income, carries the remainder into future years, and flags any repurchase inside the 30-day wash sale window. It also shows which losses to realize first, because a loss offsets short-term gains taxed at ordinary rates before it touches lower-taxed long-term gains.
Worked example
A concrete input and expected output from the current implementation.
Input
Long-term gains: $6,000
Long-term losses: $10,000
Short-term gains: $0
Short-term losses: $0
Filing status: Single
Taxable income: $80,000
->
Expected output
Net long-term loss: $4,000. Deductible against ordinary income this year: $3,000 at your 22% marginal rate = $660 tax saved. Carryover to future years: $1,000 (worth about $220 at the same rate). Wash sale check: no repurchase of the sold positions within 30 days of the sale - no issues.
The $10,000 loss first cancels the $6,000 long-term gain, leaving a $4,000 net loss. Only $3,000 can be deducted against ordinary income per year, so the saving is $3,000 times the 22% marginal rate for a single filer at $80,000 taxable income, and the remaining $1,000 carries forward.