About CapitalCalc

We build free, IRS-accurate capital gains tax calculators that help individuals and investors understand exactly what they owe — without the complexity, cost, or confusion of traditional tax software.

Our Mission

At CapitalCalc, we make IRS-accurate tax calculations accessible to everyone. We were built by engineers and finance professionals who recognized a fundamental problem: millions of Americans sell investments each year, yet most have no easy way to understand the tax consequences of those sales before they file.

Our mission is to bridge that gap. We provide free, transparent capital gains tax calculators that use the exact same tax brackets, thresholds, and methodologies prescribed by the Internal Revenue Service. Whether you sold a single stock position or an entire portfolio of assets, our tools give you a clear picture of your federal and state tax liability in seconds.

We believe informed investors make better decisions. By understanding the tax impact of a sale before you execute it, you can time dispositions strategically, harvest losses effectively, and keep more of what you earn.

How We Ensure Accuracy

Accuracy is the foundation of everything we build. Tax calculations are not a place for estimates or approximations — even a small error in bracket thresholds or rate application can lead to materially incorrect results. Here is how we maintain precision across every calculator on our platform:

Primary IRS Sources

All federal tax brackets and thresholds are sourced directly from IRS Revenue Procedures. For the 2026 tax year, our calculations reflect the rates and brackets published in Rev. Proc. 2025-32, which contains the official inflation-adjusted figures for taxable years beginning in 2026. We cross-reference these against IRS Publication 550 (Investment Income and Expenses) and the Schedule D instructions to ensure our calculation logic matches the IRS's own methodology.

State-Level Verification

State capital gains tax rates are verified against each state's official Department of Revenue publications. Because state tax treatment of capital gains varies significantly — from states with no income tax to those with complex tiered brackets — we individually research and validate rates for all 50 states plus the District of Columbia.

Ongoing Maintenance

Tax law changes every year. We update our calculators annually as new IRS guidance is published, typically in the fourth quarter of the preceding year when Revenue Procedures are released. Our update process includes a full regression test against prior-year calculations to ensure continuity and correctness.

Validation Methodology

• All brackets sourced directly from IRS Revenue Procedures (Rev. Proc. 2025-32 for 2026)
• State tax rates verified against each state's Department of Revenue publications
• Calculation logic cross-checked against IRS Publication 550 and Schedule D instructions
• Results compared against worked examples in IRS publications to confirm accuracy
• Rates updated annually as new IRS guidance is published

Our Team

CapitalCalc was created by a team of software engineers and financial analysts passionate about making tax calculations transparent and accessible. Our team members have backgrounds spanning fintech, tax preparation software, and financial planning — giving us the unique combination of technical expertise and domain knowledge needed to build truly reliable tax tools.

Our engineering team brings experience from building high-scale financial applications where precision and reliability are non-negotiable. Our finance team contributes deep knowledge of tax code, IRS procedures, and the practical realities of tax planning that everyday investors face.

Together, we share a common frustration: that accurate tax information has historically been difficult to access without paying for expensive software or professional advice. CapitalCalc exists to change that by putting IRS-accurate calculations directly in the hands of investors, for free.

What Makes Us Different

There are many tax calculators on the internet, but most provide rough estimates, use outdated brackets, or exist primarily to funnel users into paid products. CapitalCalc takes a fundamentally different approach:

• 100% free federal calculations, forever. Our core federal capital gains calculators will always be free. We believe basic tax calculations are a public good, not a premium feature.
• No login required, no personal data stored. All calculations happen in your browser. We never ask for your name, Social Security number, or any identifying information. Your financial data stays on your device.
• IRS-aligned methodology, not estimates. We don't use simplified rules of thumb. Our calculators apply the actual IRS bracket structure, including the Net Investment Income Tax (NIIT), qualified dividend treatment, and proper short-term vs. long-term classification.
• Educational guides alongside every calculator. Numbers without context are not helpful. Each calculator includes explanatory content that helps you understand what the results mean and how the tax code applies to your situation.
• Regular updates as tax laws change. Tax brackets are adjusted for inflation annually. New legislation can change rates and rules. We commit to keeping our calculators current so you always have access to the latest figures.

Editorial Standards

We hold ourselves to rigorous editorial standards because we understand that people make real financial decisions based on the information we provide. Every piece of content on CapitalCalc goes through a structured review process:

• Fact-checked against IRS publications — All tax rates, thresholds, and procedural information are verified against the primary IRS source documents before publication.
• Calculator results validated against known examples — We test our calculators against worked examples from IRS publications and professional tax preparation software to confirm output accuracy.
• Content reviewed and updated annually — Every page on our site undergoes an annual review to ensure information remains current with the latest tax law changes and IRS guidance.
• Clear disclaimers about scope and limitations — We are transparent about what our calculators can and cannot do. We clearly state assumptions, simplifications, and scenarios that may require professional guidance.

Our editorial process is designed to ensure that every calculator and every piece of content meets the same standard: accurate enough that a CPA would reach the same result using the same inputs.

Contact Us

We value feedback from our users. Whether you have a question about a calculation, a suggestion for a new feature, or notice something that needs correction, we want to hear from you.

Reach us at: [email protected]

We aim to respond to all inquiries within two business days. For questions about specific tax situations, please note that while we can explain how our calculators work, we cannot provide individualized tax advice.