Capital Gains Tax Calculator Guide
A capital gains tax calculator estimates the tax owed when you sell an investment for more than you paid, distinguishing between short-term and long-term rates based on holding period.
What Are Capital Gains?
A capital gain occurs when you sell an asset for more than its purchase price (cost basis). The gain is classified as short-term (held one year or less, taxed as ordinary income) or long-term (held more than one year, taxed at preferential rates of 0%, 15%, or 20% depending on your income bracket).
Key Inputs
Purchase Price and Sale Price
Your cost basis includes the original purchase price plus any transaction costs (commissions, fees). The sale price is the gross proceeds minus selling costs. The difference is your capital gain or loss.
Holding Period
The time between purchase and sale determines the tax rate. Assets held over one year qualify for long-term rates. This distinction can mean the difference between a 37% tax rate (short-term, highest bracket) and a 20% rate (long-term).
Tax-Loss Harvesting
Capital losses offset capital gains dollar-for-dollar. If you have $10,000 in gains and $6,000 in losses, you only pay tax on $4,000. Up to $3,000 in net losses can be deducted against ordinary income annually, with excess carried forward to future years.
State Taxes
Many states also tax capital gains. Some states like California tax them as ordinary income (up to 13.3%), while states like Texas and Florida have no state income tax. The calculator should account for both federal and applicable state taxes for accurate planning.