Calculators

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

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 ›

When a tool isn’t enoughEvery calculator links to the service or model that covers the rest of the question.Send an inquiry

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.

All services

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

Start with a calculator

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.

All models

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 ›

Rather have me run it?I can build the reporting package or run the analysis as an engagement.Send an inquiry

Loan amortization calculator

See your monthly payment, total interest, and payoff timeline — and what an extra payment each month actually saves you.

Loan amount

Rate (% APR)

Term (years)

Extra / month

Year	Principal paid	Interest paid	Ending balance

Need a schedule for an actual loan, with the entries for your books? I build loan and debt schedules, with the interest and principal split for each period, as part of reporting and modeling work.

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Estimates only, for planning purposes. Assumes a fixed rate and equal monthly payments; taxes, insurance, and fees are not included.