Capital Gains Flat-Rate Estimate CalculatorFree online financial calculator — instant results, no sign-up
Estimate tax on a realized gain using a user-supplied applicable tax rate.
Estimates only, based on the inputs and assumptions shown. This is not financial, investment, tax, or legal advice. Prices, rates and local rules may change; crypto scenarios do not predict returns. Confirm important decisions with a qualified professional.
Sign in to save results and favorites.
About the Capital Gains Flat-Rate Estimate Calculator
The Capital Gains Flat-Rate Estimate Calculator estimates tax on a realized gain by subtracting adjusted cost basis and selling fees from sale proceeds, then applying the gains tax rate you supply. It also shows proceeds remaining after fees and estimated tax. This tool does not determine which tax rate applies to your sale.
- Sale proceeds ($)
- The gross amount received from the sale before subtracting selling fees or estimated tax, entered in dollars; the default is $25,000.
- Adjusted cost basis ($)
- The asset's tax basis after applicable adjustments, entered in dollars; the default is $18,000.
- Selling fees ($)
- Sale-related costs deducted from proceeds when estimating the realized gain, entered in dollars; the default is $100.
- Applicable gains tax rate (%)
- The flat tax rate you want applied to a positive realized gain, entered as a percentage; the default is 15%.
Formula and method
G = P − B − F; T = max(G, 0) × (r / 100); N = P − F − T.
- PGross sale proceeds, in dollars.
- BAdjusted cost basis, in dollars.
- FSelling fees, in dollars.
- rUser-supplied applicable gains tax rate, expressed as a percentage.
- GRealized gain or loss, in dollars.
- TEstimated gains tax, in dollars, with no tax benefit calculated for a loss.
- NProceeds after fees and estimated tax, in dollars.
Subtract adjusted cost basis and selling fees from gross sale proceeds to find the realized gain or loss. Apply the supplied percentage rate to a positive gain; use zero estimated gains tax when there is no gain. Finally, subtract selling fees and estimated tax from sale proceeds. With the default inputs, G = $25,000 − $18,000 − $100 = $6,900.00; T = $6,900 × 0.15 = $1,035.00; and N = $25,000 − $100 − $1,035 = $23,865.00.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Sale proceeds25000 $
- Adjusted cost basis18000 $
- Selling fees100 $
- Applicable gains tax rate15 %
Results
- Realized gain or loss$6,900.00
- Estimated gains tax$1,035.00
- Proceeds after fees and estimated tax$23,865.00
How to use the Capital Gains Flat-Rate Estimate Calculator
- 1Enter gross sale proceeds before selling fees; the default is $25,000.
- 2Enter the asset's adjusted cost basis; the default is $18,000.
- 3Enter selling fees separately; the default is $100, and these fees should not already be deducted from the proceeds entered.
- 4Enter the applicable gains tax rate as a percentage, using 15 for the default 15% rate.
- 5Review the realized gain or loss, estimated gains tax, and proceeds after fees and estimated tax, checking that the basis and rate are appropriate for your sale.
Reading your result
Realized gain or loss shows the sale's result after subtracting basis and selling fees: the default result of $6,900.00 is a gain, while a negative result indicates a loss. Estimated gains tax is the flat-rate estimate on a positive gain: $1,035.00 at the default 15% rate. Proceeds after fees and estimated tax is the amount remaining from the sale after those two deductions: $23,865.00. This last figure is not profit because it includes recovery of the asset's cost basis.
Limitations
This is a single-sale, flat-rate estimate, not a calculation of your final tax liability. It assumes the supplied adjusted basis, selling fees, and tax rate are appropriate and that fees have not been counted twice. It does not determine tax treatment from asset type, holding period, income, filing status, or jurisdiction, and it does not automatically account for exemptions, exclusions, graduated rates, depreciation recapture, surtaxes, or state and local taxes. It does not net gains against other losses, apply carryforwards, or estimate deductions or refunds from a loss. Proceeds after fees and estimated tax excludes loan payoffs and other cash obligations. Verify applicable rules before using the result for tax planning or filing.
Common questions
Does the default 15% rate mean my sale qualifies for that rate?+
No. The 15% value is only a starting input. You must supply a rate appropriate to your circumstances; the calculator does not assess eligibility for capital gains rates or distinguish short-term from long-term treatment.
Should I enter sale proceeds before or after selling fees?+
Enter proceeds before fees and list the fees separately. With the defaults, enter $25,000 in proceeds and $100 in fees so the calculator deducts the fees only once.
Why are proceeds after fees and estimated tax $23,865.00 when the gain is only $6,900.00?+
The $6,900.00 gain excludes the $18,000 adjusted cost basis. The $23,865.00 proceeds figure retains that recovered basis and subtracts only the $100 selling fees and $1,035.00 estimated tax from the $25,000 sale proceeds.
What happens if adjusted cost basis and selling fees exceed sale proceeds?+
The calculator reports a realized loss and estimates gains tax as zero. It does not turn the loss into a tax refund or calculate whether it can offset other gains or income.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
Further reading
You might also like
Income Tax Calculator
Estimate 2026 US federal income tax (standard deduction).
Salary Calculator
Convert pay between hourly, daily, weekly, monthly and annual, with and without time off.
Marriage Tax Calculator
Marriage penalty or bonus for two incomes.
Estate Tax Calculator
Estimated US federal estate tax above the exemption.
Take-Home-Paycheck Calculator
Net pay after federal tax, FICA and state tax.
Overtime Pay Calculator
Calculate weekly gross pay with a configurable overtime threshold and premium.
Results are estimates for informational purposes and are not financial, medical or legal advice.