Tax on Business Sale Calculator for Tech Founders
Planning your startup exit? This calculator gives you a fast, founder-friendly estimate of federal and state capital gains taxes, including how much you could eliminate using QSBS.
Calculate Your Exit Tax Liability
This calculator models long-term vs. short-term treatment, applies QSBS eligibility rules, and incorporates optional state modeling with QSBS conformity to give you ballpark numbers quickly.
Want more precision? Our Advanced Exit Modeling Calculator, which we only use during private founder strategy sessions, is significantly more powerful. It handles QSBS trust stacking across multiple trusts and taxpayers, state residency modeling, §1045 rollovers, options, earnouts/holdbacks, ordinary income paid at closing, and multi-entity structures. You’ll see the difference below. Schedule a conversation with us to work with the advanced calculator.
KEYSTONE RECOGNITION
Disclaimer: Tax legislation varies across states, including QSBS exclusions. This tool cannot verify your actual QSBS eligibility or account for state, local, or individual tax circumstances. Consult a qualified tax advisor before making any financial decisions based on these estimates. Results are purely illustrative. This is not tax advice.
Beyond the Basics: Advanced Exit Tax Planning
This calculator gives you a directional starting point. But real founder exits involve dozens of tax and deal-structure variables that can materially change your after-tax outcome.
Our proprietary Advanced Exit Modeling Calculator is not available publicly due to its complexity and the risk of user error. It is used only during private founder strategy sessions with our team.
This advanced engine models:
- QSBS multiplication / trust stacking strategies across multiple taxpayers
- Per-taxpayer QSBS cap optimization and basis planning
- State residency modeling
- State QSBS conformity/non-conformity
- §1045 rollover opportunities & deferral strategies
- Entity and trust structuring for enhanced QSBS caps
- Charitable giving timing (DAFs, CRTs)
- Options & ordinary income at closing (AMT, Medicare, withholding mechanics)
- Earnouts, rollover equity, holdbacks, and multi-entity multi-taxpayer deal structures
- Sequencing strategies for maximizing all QSBS caps
- Simultaneous founder + trust + state comparisons
- Full NIIT, AMT, partial QSBS, and surtax modeling
- Scenario comparison “no planning” vs. “advanced planning” results
- Detection of planning headroom ($3M–$15M+ opportunities are common)
These insights cannot be reliably generated using an online tool. They need human review and guidance.
Many of these advanced strategies are proprietary and case-specific. We’ve developed an internal modeling tool that accounts for all these variables, but we don’t publish it publicly due to the potential for human error.
Want to walk through your specific situation with our team and get precise, personalized projections?
What the Simple Calculator Models
- Federal & State Tax Estimates using effective long-term and short-term capital gains rates
- QSBS Eligibility & Exclusion Analysis
- Supports historical 50%, 75%, 100% QSBS tiers
- Supports post-OBBBA 3/4/5-year requirements so you can model future exits and hypothetical holding periods
- Automatically detects holding period and applies QSBS exclusion percentage
- QSBS Cap Mechanics (Simple Mode)
- Applies the correct $10M or $15M cap
- Incorporates 10× basis rule in a simplified format
- State Conformity Modeling
- Full Conform (NY, CO, etc.)
- No Conform (CA, PA, D.C. etc.)
- No-income-tax states (TX, FL, NV, WY, etc.)
- *D.C. change: Beginning in 2025, D.C. no longer conforms to QSBS. QSBS is taxed like regular gain.
- Effective Total Tax Rate Summary
- Long-term vs. Short-term Capital Gains Allocation
This helps founders understand “roughly how much tax I’ll owe”, “how much QSBS helps”, and “what I’ll have left after tax.”
What Requires the Advanced Calculator (Private Session Only)
These items cannot be reliably modeled in the public tool:
- QSBS stacking across multiple trusts/taxpayers
- State residency planning
- Equity rollovers and §1045 rollovers
- Option grant modeling, AMT, and ordinary income at closing
- Earnouts, escrows, multi-entity structures
- Rollover equity modeling (including basis shifts)
- Founder vs. spouse vs. trust-level outputs
- Sequencing strategies to maximize multiple QSBS caps
- Simulation of “with planning” vs. “no planning” scenarios
- Multi-year planning (toggling alternative sale dates and partial liquidity events)
The advanced modeling session consistently identifies meaningful tax-savings opportunities.
For these sophisticated scenarios, connect with our team to use our proprietary advanced calculator during a consultation.
Request a Private Advanced Modeling Session
The public calculator gives you a directional estimate. But founders with $20M+ exits almost always benefit from precision modeling, often 12–36 months before liquidity.
Two pathways:
1. Advanced Calculator Consultation (Private Session)
Walk through your situation, equity composition, grant history, QSBS eligibility, state residency, trust options, and deal structure using our proprietary modeling engine. Not available publicly.
2. Pre-Exit Strategic Advisory
We work with founders up to three years prior to a liquidity event, at no charge during the pre-liquidity phase, to model, structure, and optimize every part of the transaction.
Most founders leave significant assets on the table simply because they never ran these scenarios early enough.
Take the Next Step
Is your exit strategy optimized for tax efficiency?
Most founders underestimate the available planning pathways, especially around QSBS, trust structuring, jurisdiction, option strategy, multi-entity planning, and charitable structuring. Our modeling often identifies $3M–$15M+ in potential, tax savings opportunities.
Connect with our founder to discuss your specific exit scenario. We’ll review your QSBS qualification, explore state planning opportunities, and identify trust strategies most advisors miss.
Important Disclaimers
This calculator and information are for educational purposes only and do not constitute tax, legal, or financial advice. Capital gains tax calculations involve complex federal and state rules that vary based on individual circumstances.
QSBS qualification requirements are intricate and depend on factors including:
- Corporate structure and activity—the issuer must be a domestic C corporation engaged in an active trade or business within the applicable asset thresholds.
- Gross asset limits—$50 million for pre-OBBBA issuances and $75 million for post-OBBBA issuances.
- Nature of business—the issuer must not operate in excluded industries such as services, finance, or hospitality, and passive assets should remain below approximately ten percent of total asset value.
- Stock issuance and ownership—shares must be originally issued to, or received through a qualifying transfer by, a non-corporate holder.
- Compliance considerations—investors must satisfy holding-period, redemption, and reorganization requirements to maintain QSBS eligibility.
Professional guidance is essential: Given the complexity and high stakes of founder exits, consult with qualified tax professionals and wealth advisors familiar with venture-backed company liquidity events. Results are estimates based on current tax law and the information provided. Actual tax liability may differ based on changes in tax law, individual circumstances, and factors not captured in this calculator.
Disclaimer: The information and opinions provided in this material are for general informational purposes only and should not be considered as tax, financial, investment, or legal advice. The information is not intended to replace professional advice from qualified professionals in your jurisdiction.
Tax laws and regulations are complex and subject to change, and their application can vary widely based on the specific facts and circumstances involved. Any tax information or advice in this article is not intended to be, and should not be, used as a substitute for specific tax advice from a qualified tax professional.
Investment advice in this article is based on the general principles of finance and investing and may not be suitable for all individuals or circumstances. Investments can go up or down in value, and there is always the potential of losing money when you invest. Before making any investment decisions, you should consult with a qualified financial professional who is familiar with your individual financial situation, objectives, and risk tolerance.
