Tax applies to gain, not sale cash
Capital gain in this simple sale model is proceeds minus cost basis, with the entered rate applied only when that difference is positive. The formula separates a gain from sale cash: receiving $42,000 does not mean $42,000 is taxable when $30,000 of that amount recovers basis.
A basis-and-proceeds example
At the defaults, $42,000 proceeds less $30,000 basis leaves a $12,000 gain. Fifteen percent of that gain is $1,800, leaving $40,200 after this estimated tax. A $12,000 loss produces no tax here, but that does not state how a real loss may be used.
Basis needs its own records
Cost basis is often more complicated than the original purchase price. Reinvested distributions, improvements, splits, prior depreciation, gifts, inherited assets, fees, and foreign-currency effects can alter it. Confusing proceeds with gain is the usual reason a quick estimate becomes wildly wrong.
Portfolio and holding rules are absent
Use this tool for a single asset sale where basis and rate have already been established. It does not distinguish holding periods, net gains across a portfolio, apply loss offsets, identify special asset rules, or calculate surtaxes. Brokerage records and tax rules govern those questions.
Keep the disposal trail
Save the acquisition evidence, adjustment record, disposal costs, and sale date with any estimate. That trail is more valuable than a remembered percentage when a return is prepared later.
Timing can alter the facts even when the sale amount is unchanged. A sale date, settlement date, holding period, and residence or account status may each matter under applicable rules. This calculator intentionally leaves those classifications outside the rate input. Before acting on a sale, assemble trade confirmations, purchase records, reinvestment history, and transaction fees. If the asset was received by gift or inheritance, do not assume the cash paid by the seller establishes the tax basis; that is exactly the kind of fact the simple subtraction cannot infer.
A result should be labelled with the asset and sale date. That prevents a provisional scenario from being confused with a final tax record after another transaction changes the facts.
Tax-tool index
All tax calculators · Self-Employment Tax Estimator · Property Tax Estimator