Guides & tools
Answers for US business owners, organized by the decision in front of you.
In-depth guides, free calculators and 80+ articles on entity choice, taxes, equity, R&D credits and finance operations. Written and maintained by our CPAs, checked against IRS and state sources.
Free calculators
All tools →- Delaware Franchise Tax CalculatorThis calculator works out your Delaware corporate franchise tax under both statutory methods, the authorized shares method and the assumed par value capital method, and tells you which one is lower. It is built for Delaware C-Corps with large share counts and small balance sheets, the startups that open a five-figure bill from Delaware and owe a few hundred dollars instead.
- Texas Franchise Tax CalculatorThis calculator estimates the Texas franchise (margin) tax a taxable entity owes on its 2026 or 2027 report, comparing the four margin methods and the EZ computation side by side. It is for corporations and LLCs doing business in Texas, including Delaware companies registered in Texas, that want to know whether they owe anything above the $2.65 million no-tax-due threshold and which form gets them the lowest number.
- 83(b) Election Deadline CalculatorEnter the date your restricted stock was transferred and this tool returns the last day to file your Section 83(b) election, 30 days later, moved to the next business day when that date falls on a weekend or federal holiday. It is for founders, early employees and advisors receiving unvested stock or early-exercising options, and it also tells you which IRS service center to mail to if you file on paper.
- S-Corp Tax Savings CalculatorThis calculator estimates how much a profitable single-owner LLC or sole proprietorship would save each year by electing S corporation status, after subtracting the added costs of payroll, a separate Form 1120-S and state S-corp taxes. It is for owner-operators of service businesses and small companies with steady profit, not for venture-backed startups, which generally need to stay C-Corps.
- Estimated Tax CalculatorThis calculator works out the quarterly estimated tax payments needed to avoid an IRS underpayment penalty, using the safe-harbor rules for individuals filing Form 1040-ES and for C corporations. It is for founders, freelancers and S-corp owners with income that has no withholding, and for C-Corps that have started to show taxable income.
- R&D Tax Credit CalculatorThis calculator estimates your federal research credit under the alternative simplified credit (ASC) method of IRC §41(c)(4), including the reduced-credit election and how much a qualified small business could apply against payroll tax. It is for startups and growing companies that pay engineers, scientists or contractors to build new products, processes or software.
- Sales Tax Nexus CheckerThis checker compares your sales into each state against that state's economic nexus threshold and flags where you likely need to register and collect sales tax. It is for ecommerce sellers, SaaS companies and other remote businesses selling across state lines that want a quick first pass before talking to an advisor about registration.
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Entity choice & Delaware
International founders
State tax guides
Rates, nexus rules, credits and deadlines for the states startups most often operate in.
See all state guides