US Tax Calculator Guide: S-Corp, RSU, Crypto & Capital Gains
How to use free tax calculators for S-Corp salary splits, RSU withholding, crypto disposals, and AMT on option exercises—without replacing your CPA.
US tax planning for individuals and small businesses spans S-Corp payroll splits, equity compensation (RSUs and ISOs), crypto disposals, and traditional capital gains. None of these tools replace a CPA—but they help you sanity-check scenarios before a professional files your return.
S-Corp reasonable salary
An S-Corp can reduce self-employment tax by splitting profit into W-2 wages (subject to payroll tax) and distributions (not subject to SE tax on the distribution portion). The IRS expects a reasonable salary for services you perform. Model salary vs distribution before you elect S status.
RSUs and stock options
RSUs are taxed as wages at vest. ISO exercises can trigger alternative minimum tax (AMT) on the bargain element. Withholding on paychecks may not cover the full bill—plan estimated payments.
Crypto capital gains
Each disposal (sell, swap, spend) is a taxable event in the US. Holding more than one year often qualifies for long-term rates; short-term generally follows ordinary income brackets. Track cost basis per lot.
Limitations
Educational only Fynvorax calculators use simplified federal assumptions. State tax, NIIT, AMT phase-outs, and carryforwards are not fully modeled. Confirm numbers with a licensed tax preparer.