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Stock Tax Estimator

Estimate tax on a stock sale from proceeds, adjusted basis, selling costs, usable capital losses, and rates you select. The result helps compare net outcomes before selling shares or setting aside funds after a transaction.

The model focuses on a single net capital gain. It does not determine wash-sale adjustments, holding period, qualified small-business treatment, employee-stock compensation, or jurisdiction-specific surtaxes.

Enter your assumptions

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Result
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Estimated result
Net taxable gain—
Capital-gain tax—
Surcharge—
Estimated total tax—

1. Use one tax period
Enter all income, deductions, payments, and rates for the same tax year or modeled period.

2. Enter the source amounts
Use records or a prepared estimate rather than mixing gross and net figures.

3. Apply the correct treatment
Choose rates and deductions that match the jurisdiction, taxpayer, asset, or entity being modeled.

4. Review the breakdown
Check intermediate values for duplicated deductions, missing payments, or an unintended zero result.

5. Test another scenario
Change one assumption at a time to see which input drives the estimate; use Reset to restore defaults.

Net taxable gain = max(0, Proceeds − Adjusted basis − Selling fees − Loss offsets) Capital-gain tax = Net taxable gain × Capital-gain rate Surcharge = Net taxable gain × Surcharge rate Total estimated tax = Capital-gain tax + Surcharge

What the result means

The displayed result applies only to the assumptions entered and the simplified calculation shown above.

This is a planning estimate, not tax advice. Tax rules vary by jurisdiction, entity type, filing status, holding period, deductions, credits, and tax year.

Given: Proceeds of $42,000, adjusted basis of $30,000, $50 of fees, $2,000 of loss offsets, a 15% gain rate, and no surcharge.

Calculation: Gain = $42,000 − $30,000 − $50 − $2,000 = $9,950. Tax = $9,950 × 0.15 = $1,492.50.

Result: Estimated tax is $1,492.50.

What is adjusted cost basis?

It is the original basis after relevant adjustments such as reinvested distributions, returns of capital, splits, or disallowed losses.

Should dividends be included?

No. This page models a sale gain. Dividend income should be estimated separately under its applicable treatment.

How does holding period affect the input rate?

Short- and long-term gains may use different rates. Select the rate that matches the shares sold and the applicable rules.

What if the calculation produces a loss?

This calculator floors the taxable gain at zero. Record the actual loss separately because it may offset other gains or carry to another period.

Can I combine several stock sales?

Yes, after computing correct basis and gain or loss for each lot, you may enter aggregated proceeds, basis, fees, and allowed offsets for a consistent category.