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Calculators

Free tools built by the CPA who prepares the returns. Each one lists the rules and figures it uses.

All 12 calculators

S-Corp vs. Sole Proprietor 1099 Estimated Tax Planner Solo 401(k) and SEP-IRA QBI Deduction Estimator (§199A) Entity Comparison True Runway

Most used

S-Corp vs. Sole Proprietor ›1099 Estimated Tax Planner ›Withholding Checkup ›

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Services

Tax, books, elections and reporting for owner-run businesses and investors. I do the work myself, under an engagement letter that sets scope and fee first.

Form 1040 and California Form 540 Form 1120-S and California Form 100S Estimated payments Extensions Owner compensation The §199A deduction Shareholder basis Depreciation choices Go to the Tax page

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Withholding Checkup ›S-Corp vs. Sole Proprietor ›Rental Property Analyzer ›

Excel modelsThe reporting package, C-to-S conversion and QSBS workbooks are built the way I build them for clients.See the models

Models

Excel workbooks for reporting and tax analysis. Licensed per user or firm; you own your copy.

Financial Reporting Package v2.1 Consolidation Edition v1.0 C-Corp to S-Corp Conversion Analyzer v2.0 QSBS §1202 Analyzer v1.0

What’s inside

21 tabs, 28,550 formulas (FRP) ›§1374 and LIFO recapture (C→S) ›Pre- and post-2025 §1202 rules ›

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Calculators

12 free calculators

Built and maintained by the CPA who prepares the returns. Results are estimates for planning, not advice for your situation.

The index

BUS-01S-Corp vs. Sole ProprietorEstimates self-employment tax savings from an S election, after a reasonable salary and the cost of running payroll.Business owners BUS-021099 Estimated Tax PlannerQuarterly federal and California estimates using the 90%, 100% or 110% safe harbor, with an option for uneven income.Business owners BUS-03Solo 401(k) and SEP-IRAMaximum contribution under each plan by entity type and age, and which plan allows more.Business owners BUS-04QBI Deduction Estimator (§199A)The 20% qualified business income deduction, with the income thresholds and the specified service trade or business rules.Business owners BUS-05Entity ComparisonSole proprietorship, S-corporation and C-corporation compared on the same profit, with optional California entity taxes.Business owners BUS-06True RunwayA cash forecast by month and by week under bad, base and good scenarios, with a reserve for taxes.Business owners IND-01Withholding CheckupCompares federal withholding to the estimated tax on your return and suggests a Form W-4 change.Individuals IND-02California Take-Home PayGross pay to net pay after federal tax, FICA, California tax and SDI.Individuals IND-03Itemize vs. Standard DeductionCompares itemized deductions with the standard deduction and uses the larger.Individuals IND-04Life-Event W-4 HelperA checklist of Form W-4 changes after a marriage, a new child, a home purchase or a side job.Individuals RE-01Rental Property AnalyzerNet operating income, cap rate, cash-on-cash return and debt service coverage for a rental property.Real estate DEBT-01Loan AmortizationPayment, total interest and a full schedule, with the savings from extra principal payments.Loans and debt

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