Cost basis is the purchase value plus costs connected with the purchase and any allowed basis adjustments. The calculator keeps those items visible so the tax estimate is easier to audit.

Does it handle exact local tax law?

No. It is a planning model. Local rules can depend on asset type, residency, exemptions, loss offsets, reporting forms, and holding period.

Capital Gains Calculator

Tax, Cost Basis & ROI

Transaction Setup

Asset Name

Asset Class

Quantity

Price Setup

Buy Price

Sell Price

Fees, Tax & Basis

Buy Fee

Sell Fee

Basis Adjustments

Tax Rate

Holding Period

Tax Basis Desk

Separate price movement from tax drag before you sell

Capital gains are not just “sell price minus buy price.” A professional estimate starts with cost basis, subtracts sale costs, classifies the holding period, then applies an estimated tax rate. The IRS explains the distinction between short and long term in Topic 409.

"The number that matters is after-tax cash kept, not the headline gain."

Basis First

Track purchase fees and basis adjustments. The IRS notes that basis often starts with cost and related purchase expenses in Topic 703.

Tax Only On Gains

The calculator applies tax only when realized gain is positive; losses may have separate offset rules.

Holding Period

Holding period can change treatment. Use the term flag as a prompt to check local rules before selling.

Frequently Asked Questions

It estimates cost basis, net proceeds, realized gain, tax on positive gain, and after-tax net gain. For U.S. context, compare the model with IRS Topic 409 and IRS Topic 703.

Frequently Asked Questions

It estimates cost basis, net proceeds, realized gain, tax on positive gain, and after-tax net gain. For U.S. context, compare the model with IRS Topic 409 and IRS Topic 703.