Tax
Capital Gains Tax Calculator
Calculate adjusted basis, net sale proceeds, realized gain or loss, entered-rate tax, and after-tax outcome for an asset disposal.
Adjusted cost basis-
Net sale proceeds-
Realized gain or loss-
Positive gain before exclusions or netting-
Realized capital loss-
Entered-rate tax on positive gain-
After-tax transaction gain or loss-
Decision view
Adjusted basis to after-tax gain bridge
Adjusted basis to after-tax gain bridgePurchase basis, improvements, transaction costs, net proceeds, modeled tax, and after-tax gain reconcile in one transaction path.
Exact scenario comparisonGross sale proceeds changes while all other entered assumptions remain constant.
| Gross sale proceeds | Adjusted cost basis | Net sale proceeds | Realized gain or loss | Positive gain before exclusions or netting | Realized capital loss | Entered-rate tax on positive gain | After-tax transaction gain or loss |
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How to use Capital Gains Tax Calculator
- Enter the original purchase price from the acquisition record.
- Add only capital improvements and eligible acquisition costs that belong in basis.
- Enter depreciation or other basis reductions already allowed or allowable.
- Subtract selling commissions and closing costs from gross proceeds.
- Review the signed realized result before applying any tax rate.
- Classify holding period, exclusions, recapture, and loss netting outside this arithmetic model.
Calculator guide
Understanding Capital Gains Tax Calculator
Estimate the realized gain or loss from one asset sale by reconciling sale proceeds, transaction costs, adjusted basis, capital additions, and prior basis reductions. A positive gain can then be tested with a user-entered tax rate without erasing a genuine loss.
Detailed calculation process
How the gain or loss is calculated
The transaction is reconciled before any entered-rate estimate is applied.
General formula: B = P + I + C - D; N = S - E; G = N - B; T = max(G, 0) x r; A = G - T Build adjusted basis B, derive net proceeds N, preserve the signed gain or loss G, then apply rate r only to a positive gain.
What each symbol means
Worked substitution with the default inputs
Default reconciliation: $138,000 basis + $39,000 gain = $177,000 net proceeds, and $7,800 tax + $31,200 after-tax gain = $39,000.
Recordkeeping
Build a defensible basis file
The arithmetic is simple only after the evidence is organized.
Worked situations
Practical examples
- The default values produce a $138,000 adjusted basis and $177,000 net proceeds, so the realized gain is $39,000; at 20%, modeled tax is $7,800 and the after-tax gain is $31,200.
- If net proceeds are $110,000 against a $138,000 basis, the calculator reports a $28,000 realized loss rather than silently replacing the loss with zero.
Better inputs
Useful tips
- Keep settlement statements, invoices, improvement records, and depreciation schedules together.
- Do not classify repairs as improvements without checking the applicable rules.
- Run short-term, long-term, recapture, and surtax components separately when they apply.
Before relying on the result
Limitations and common mistakes
- The page does not classify short-term and long-term gains or determine preferential rates.
- Loss limitations, carryovers, wash sales, exclusions, installment sales, NIIT, and recapture are excluded.
- The entered percentage is applied to the whole positive modeled gain and may not match a return.
Reference
Key terms
- Adjusted basis
- Original basis after capital additions and required reductions.
- Amount realized
- Sale proceeds after selling costs used in the gain-or-loss comparison.
- Capital improvement
- A qualifying addition that increases basis rather than a current repair expense.
- Basis reduction
- Depreciation or another adjustment that lowers basis.
- Realized gain
- Positive net proceeds minus adjusted basis.
- Capital loss
- The amount by which adjusted basis exceeds net proceeds.
Important note
Authority to review: IRS Topic 409 and Publication 550. The calculator supplies transaction arithmetic, not holding-period classification or return treatment.
Frequently asked questions
Why is depreciation subtracted from basis?
Depreciation allowed or allowable generally reduces adjusted basis before gain or loss is measured.
Does a negative result mean the full loss is deductible?
No. The result is the realized transaction loss; deductibility and annual limits require separate tax analysis.
Does the calculator choose a short-term or long-term rate?
No. Enter a scenario rate only after determining the holding-period treatment.
Are selling costs deductible separately?
Here they reduce net proceeds so they are not deducted a second time.
Does the result include NIIT?
No. Net investment income tax is outside this model.
Can I use this for a home sale?
Only for basic transaction arithmetic; residence exclusions, mixed use, depreciation, and recapture need separate review.