FREE TAX TOOLS

Free tax calculators and planning tools

Use a focused tool to organize the facts behind an ISO exercise, estimated-tax, sales-tax, or rental-property sale question before deciding whether you need individual CPA help.

No sign-up
No sensitive information needed
General information only

CHOOSE A STARTING POINT

Work through the question closest to your situation

Each tool explains its scope, sources, and limits before asking for general planning information.

INCENTIVE STOCK OPTIONS

ISO AMT exercise-spread calculator

Use Form 3921 boxes 3, 4, and 5 to estimate exercise cost, exercise-date value, and the ISO spread that may affect a broader Form 6251 review.

For one ISO exercise at a time
Calculates the spread—not final AMT or tax due
Figures stay in your browser

Use the ISO Spread Calculator Explore Equity-Compensation Tax Planning Discuss an ISO Exercise

RENTAL-PROPERTY SALE

Rental property sale tax estimator

Estimate adjusted basis, preliminary gain, a potential unrecaptured Section 1250 component, and federal rate scenarios for a narrowly defined fully taxable sale.

For one basic U.S. residential rental sale
Stops when ownership, use, assets, or transaction terms add complexity
Amounts stay in your browser

Use the Rental-Sale Estimator Explore Rental-Property Tax Services Discuss a Rental-Property Sale

2026 FEDERAL ESTIMATED TAX

Estimated tax safe-harbor calculator

Compare the general 90% current-year benchmark with the 100% or higher-income 110% prior-year benchmark, then see how projected withholding and payments compare.

For individual federal estimated-tax planning
Uses the general 2026 safe-harbor framework
Numbers stay in your browser

Use the Estimated-Tax Calculator Explore Estimated-Tax Planning Discuss Your Estimated Taxes

MULTISTATE SALES TAX

Sales tax exposure check

Answer six operational questions to identify physical-presence, marketplace, registration, filing, notice, and multistate selling facts that may warrant a closer review.

For businesses selling across state lines
Creates a practical state-by-state review list
No answers or business data are saved

Use the Sales Tax Exposure Check Explore Sales Tax Services Discuss Your Sales Tax Situation

PRIVACY & SCOPE

Use general planning information—not tax documents

The tools do not require an account and do not save the figures or answers you enter. Anonymous tool-start, completion, and contact-click events may be measured without the values you provide.

Important limits

Do not enter Social Security numbers, tax IDs, account numbers, customer data, or confidential documents.
Results depend on the information entered, current law, payment timing, and state-specific rules.
The tools provide general information, not tax or legal advice, and do not create a CPA-client relationship.
A signed engagement agreement is required before Tavella CPA Group provides services for your specific facts.

WHEN GENERAL INFORMATION ISN'T ENOUGH

Bring the result into a conversation about your facts.

A free call can help identify the service, records, jurisdictions, and timing involved. Do not send tax documents through the public contact form.

Schedule a Free Call