US corporate tax is not "profit × one state's rate". Federal tax is a flat 21% on total US profit. States only tax you where you have nexus, and only on the share of profit matching that state's share of your US sales. Incorporated in Delaware with no operations there? Your Delaware income tax is 0. Fill in a few numbers and we'll run it properly.
US corporate tax is not simply profit times one state's rate. At the federal level a C-Corp pays a flat 21% on total US pre-tax net income, regardless of where it is incorporated. State income tax is a separate layer: only states where you have nexus can tax the profit attributable to them. This tool follows the common single sales factor approach: profit is apportioned to each nexus state by that state's share of your total US sales, then multiplied by the state rate.
Your state of incorporation does not automatically bring state income tax. If you are incorporated in Delaware or similar and have no employees, warehouse or real operations there, state income tax is often 0. Delaware still charges franchise tax and other annual fees, and "no corporate income tax" states such as Texas, Washington, Ohio and Nevada usually levy substitutes like franchise (margin) tax, B&O or CAT, so they are not truly free. The tool uses each state's top rate for a rough estimate (for example about 8.84% in California, about 7.25% in New York and about 9.0% in New Jersey), and flags the likely substitute tax for states with a 0 rate.
If you choose an LLC or partnership, the entity is pass-through: it pays no federal corporate income tax, and profit flows to the owners' individual returns, so the tool shows 0 federal tax at the company level. For owners based in China, pass-through structures also bring nonresident individual filings and withholding, so entity choice needs to be modeled as a whole. A C-Corp faces double taxation: the company pays federal tax (plus state tax where it has nexus), then dividends are taxed again at the shareholder level. Cross-border dividends commonly carry 30% withholding, which the US–China tax treaty may reduce depending on ownership and treaty conditions.
No. The 21% federal tax is calculated once, on total US profit. State tax is each state's own tax, estimated only for nexus states, on apportioned profit (sales factor in this tool) at that state's rate. You can't simply add the federal and state rates to get a combined rate, although the overall burden will be higher than 21%.
If you have no operations or sales in Delaware, Delaware income tax is generally 0, but franchise tax and similar fees still apply. State income tax actually comes from the states where you operate or sell and have nexus.
Profit is split using that state's sales ÷ total US sales, then multiplied by the state rate. Some states have historically also weighed property and payroll. For easy comparison this calculator uses the sales factor throughout; actual returns follow each state's own formula.
No. A pass-through entity pays no federal corporate income tax at the entity level; the tax shifts to the owners (or members). Cross-border owners also have filing, withholding and treaty issues, so the total burden needs its own model.
No. The results are for illustration and rough estimates only. They exclude credits, loss carryforwards, surtaxes, state-specific adjustments and full apportionment formulas. Final figures depend on your books, each state's returns and professional review.