Gleaner · Keep what’s yours
The tax losses in your
accounts are hiding.
Gleaner finds them.
A free calculator for people with investments spread across brokerages. Drop in the CSV files you already download. You see every underwater position, what selling would offset, and the wash-sale traps between your accounts.
Common questions
What is "tax-loss harvesting"?
Plain version: sell an investment for less than you paid, and the tax rules let you subtract the loss from profits you made elsewhere, so you owe less tax. Selling a losing investment on purpose for the subtraction is called tax loss harvesting. The loss already happened on paper, and selling makes it count. Your money isn't gone either, since you reinvest it somewhere else the same day. Gleaner shows you where those losses sit, because most people have some and never know.
Is this tax advice?
No. Gleaner is a calculator. It does arithmetic on the files you provide and shows you the results. You make the decisions, and anything you plan to act on is worth confirming with a tax professional. Nothing here recommends a trade.
Are capital gains taxed differently from regular income?
Yes, and the difference surprises almost everyone. Profits on investments held over a year, called long term, get their own lower schedule of 0%, 15%, or 20% depending on household income. Above roughly $250K for married filers, add another 3.8%, known to accountants as the net investment income tax or NIIT. Profits on anything held under a year get taxed like your paycheck. Gleaner's federal dropdown shows the long term schedule, since harvested losses usually offset long term gains.
What if my gains are short-term?
Then harvesting is worth even more than Gleaner estimates. Losses offset gains of the same type first, and short term gains get taxed at higher rates, so canceling them saves you more per dollar. Gleaner estimates with the long term schedule, so the number on your screen is the conservative one. Your real savings land higher.
What's a wash sale?
Buy the same investment within 30 days before or after selling it at a loss, and the IRS disallows the loss. Automatic dividend reinvestment counts as a purchase, in any account your household owns, which is how most people trip over this without noticing. Gleaner flags positions held in more than one place so you check your reinvestment settings before selling.
What's a tax lot, and why do I care?
Every time you buy or receive shares, the batch is a "lot" with its own purchase date and price. One stock holds winning lots and losing lots at the same time, and you're allowed to sell only the losers. The biggest hidden losses often live there, especially in employee stock plans. Gleaner lists lots individually so you pick exactly which ones go into your plan.
Is my data really private, and how would I know?
Yes. Gleaner has no server and no database, so there is nowhere for your information to go. Your files are read by your own browser and stored only on your device, and one button erases everything.
You don't have to take my word for it. Turn off your wifi and Gleaner keeps working. Import your files, read the whole report, download your plan, all with no connection at all. None of it would work if your information were going somewhere.
A few other ways to check. The code is public, one file to read on GitHub. The numbers are checkable, because the cost basis column matches what your brokerage already shows you. And there's no account, so there's nothing about you to store, lose, or sell.
How often should I use this?
A few times a year, when it matters: after a market drop, after selling something big, and before December 31. The app has a reminder button, which drops a year end nudge into your own calendar. No email required.
Does this work outside the US?
Not yet. Gleaner is built for US tax rules, and other countries treat investment losses differently. Canada averages your cost across all shares instead of tracking individual lots, draws no line between short term and long term, and won't let losses reduce regular income. Running a Canadian portfolio through US math would give wrong answers, so for now the tool is US only.