Capital Gains Calculator

What a capital gain actually is

A capital gain is the profit you realize when you sell a capital asset for more than you paid for it. Stocks, bonds, mutual fund shares, real estate, cryptocurrency, collectibles, and even a used car sold at a profit can all produce capital gains. The raw number is simple arithmetic: sale price minus cost basis. If you bought shares for $10,000 and sold them for $16,000, your gain is $6,000 and that is the figure the tax system cares about, not the full sale price.

The cost basis is where most of the real-world complexity hides. Basis starts as your purchase price, but it adjusts upward for certain acquisition costs like commissions and closing fees, and for capital improvements to real estate. It can adjust downward for depreciation you claimed or could have claimed. Getting basis right is the highest-leverage thing you can do, because every dollar of basis you can document is a dollar that is not taxed. The calculator takes your basis as an input precisely because the correct figure depends on records only you have.

One more distinction matters before any arithmetic: realized versus unrealized. A gain becomes real for tax purposes only when you sell. Shares that climbed from $10,000 to $16,000 on paper owe nothing until you dispose of them. This is why the timing of a sale, not just the size of the gain, is one of the few levers an individual investor actually controls.

Short-term versus long-term: the holding period that changes everything

The single most important fact about capital gains tax is that the tax system treats you very differently depending on how long you held the asset before selling. The clock runs from the day after you acquire the asset to the day you dispose of it. Hold for one year or less and your gain is short term, taxed as ordinary income at the same brackets that apply to your wages. Hold for more than one year and the gain is long term, taxed at the preferential schedule of 0%, 15%, or 20% for most taxpayers, with high earners potentially owing an additional net investment income tax.

The gap between those two regimes is the largest structural arbitrage available to ordinary investors, and it is why financial planning obsesses over the one-year mark. An investor in a 24% ordinary bracket pays 9 percentage points more on a short-term gain than on a 15% long-term gain. On a $50,000 gain that is $4,500 for doing nothing but waiting past the threshold. The calculator's worked example shows exactly this spread on a $24,000 gain.

The flip side deserves honest treatment: the one-year line is a cliff, not a slope. Selling at 11 months forfeits the entire benefit even if you would have held forever at 13 months. And the preferential rate is not a promise that waiting is always right. If the asset falls 10% during the wait, you gave up more in market value than you saved in tax. The holding period is a lever, not a law of returns; the calculator exists so you can quantify the trade before making it.

The formula, term by term

The core calculation uses four terms, and each one has a precise definition that changes the answer:

Taxable gain = sale price - cost basis. The sale price is what you actually received, after transaction costs you can substantiate. The cost basis is purchase price plus buy-side commissions and, for real estate, qualifying closing costs and capital improvements. Basis is not your down payment on a house; it is the full purchase price plus improvements, which surprises many first-time sellers.

Estimated tax = taxable gain x rate. The rate is a single number you supply, representing either your ordinary marginal rate for short-term gains or the applicable long-term rate for your bracket. Because the real rate schedule is progressive and layered with surtaxes, a single rate is an approximation. The calculator keeps the rate editable rather than hard-coding figures, so the output stays honest about what it knows.

Net proceeds = sale price - estimated tax. This is the number people actually care about: what lands in your account. On the default example inputs, a $64,000 sale with a $40,000 basis at an assumed 24% rate leaves $58,240 after an estimated $5,760 of tax. Run the same inputs at 15% and the keep-figure rises to $60,400. That two-number comparison, done before you sell, is the entire point of the tool.

• Sale price: gross proceeds you can document, ideally net of selling costs.
• Cost basis: purchase price plus acquisition costs plus capital improvements minus depreciation claimed.
• Rate: your ordinary marginal rate for short-term gains, or 0/15/20 percent schedule plus any surtax for long-term gains; enter the figure that matches your situation.

Worked example: selling stock

Suppose you bought 200 shares at $200 each, a $40,000 total cost, and you sell them for $64,000. Your basis is $40,000 (add $20 of commission if you paid one; every documented dollar of cost lowers the gain). The gain is $64,000 - $40,000 = $24,000. Now the holding period decides the rest.

Short-term case: you held 11 months. The $24,000 stacks on top of your ordinary income, and at an assumed 24% marginal rate the estimated tax is $24,000 x 0.24 = $5,760. You keep $58,240 of the sale. Because short-term gains stack on wages, they can also push other income into higher brackets in the same year, an interaction this simple calculator does not model but a real filing will show.

Long-term case: you wait 5 more weeks and sell after a full year plus a day. The same $24,000 gain now falls under the preferential schedule. For a single filer with taxable income in the middle band, an assumed 15% rate applies: $24,000 x 0.15 = $3,600 in estimated tax, leaving $60,400. The five-week wait saved $2,160 on identical numbers. That is the entire mechanical reason the calculator asks for a holding period. All figures here are illustrative; your actual rate depends on your total taxable income and current law.

Worked example: selling a house

Real estate basis works differently enough that it deserves its own walkthrough. Say you bought a home for $300,000, paid $9,000 in closing costs on the buy side, and spent $40,000 on a qualifying capital improvement, a new addition rather than a repaint. Your basis is $349,000. If you sell for $520,000 with $26,000 in selling costs, the amount realized is $494,000 and the gain is $494,000 - $349,000 = $145,000.

Two things bend this picture. First, most owners who sell a primary residence can exclude a large slice of the gain from tax entirely, up to statutory limits, if they owned and occupied the home as their main residence for at least two of the last five years. A gain inside the exclusion produces no capital gains tax at all, which is why millions of home sales generate no tax even when the paper profit is large. Check current IRS guidance for the exact limits and conditions; this calculator does not model the exclusion.

Second, depreciation recapture applies if the property was ever a rental. Every dollar of depreciation you claimed lowers your basis and is later taxed at a specific recapture rate when you sell. A $145,000 gain on a former rental behaves nothing like a $145,000 stock gain. The honest workflow is: compute your true basis from records, subtract any exclusion, then use the calculator on the remainder with an appropriate assumed rate. The example numbers above are illustrative of the arithmetic, not a prediction of any actual tax bill.

2026 Rate Context: Structure, Not Promises

This section describes how the rate structure works rather than quoting bracket tables, because exact thresholds change with inflation adjustments and this calculator is designed around rates you enter. The structure has been stable for years: short-term gains are taxed at the same seven ordinary brackets that apply to wages. Long-term gains on most assets use a three-step schedule of 0%, 15%, and 20%, with the 0% band reserved for lower taxable incomes, 15% covering the broad middle, and 20% applying at the top. High earners can add a 3.8% net investment income tax on top, and some state income taxes apply to gains as ordinary income.

A few assets sit outside the standard schedule and are worth flagging. Collectibles such as art, coins, and antiques cap out at a 28% long-term rate. Certain small-business stock can qualify for partial exclusion. Real estate depreciation is recaptured at a specific rate regardless of your bracket. Unrecaptured Section 1250 gain, collectibles, and qualified small business stock each have their own lines on the schedule, which is one more reason a single flat rate is a model, not a mirror.

For current-year figures, the authoritative sources are IRS Topic 409 and the annual inflation-adjustment revenue procedure, both linked in the sources block on this page. The calculator's editable rate field exists so that when brackets shift, the tool does not silently go stale: you supply the rate that matches your situation and the arithmetic stays correct. That design choice trades convenience for honesty, and it is deliberate.

Loss offsets and netting: when the sale does not go your way

Capital losses work in the opposite direction of gains and are the tax system's one consolation prize. When you sell an asset for less than basis, the loss can offset gains of the same character first: short-term losses against short-term gains, long-term losses against long-term gains. Leftover losses cross over to the other category, and whatever remains after that can offset up to a statutory limit of ordinary income per year, with the excess carried forward indefinitely to future years.

The mechanical consequence is that tax is owed on net gains, not on every winning sale in isolation. If you realize a $30,000 long-term gain and a $10,000 long-term loss in the same year, the taxable long-term gain is $20,000 and that is the figure the rate applies to. Harvesting losses deliberately, selling positions that are underwater to realize the loss while keeping overall exposure, is a common and legitimate strategy built entirely on this netting logic. Watch the wash-sale rule for securities: buying a substantially identical asset within the window around the loss sale disallows the deduction.

Netting is where this simple calculator reaches its honest limit. The tool estimates tax on the single gain you enter. A real tax year with multiple sales, both characters of gains and losses, carryforwards from prior years, and state taxes produces a different number, usually a better one if you have losses available. Use the calculator for per-sale decisions, then confirm the full-year picture with tax software or a professional. This page is general information, not tax advice, and your situation may have features the model does not see.