How FiscalCalc Formulas Work

Where formulas come from

FiscalCalc uses three primary sources for all formula development. Each was chosen because it is a recognized authority in its domain and publishes its methodology publicly — meaning you can check our work against the same documents we used.

We do not source formulas from competitor calculator sites, general search results, or AI-generated summaries. All formula inputs trace back to one of the three primary sources above.

What “formula shown” means

Below every calculator result, FiscalCalc displays four things:

1. The formula itself — the actual equation used to produce your result, written out with variable names defined.
2. Variable definitions — what each input represents and how it maps to your inputs in the calculator above.
3. Worked example — the formula applied to a concrete scenario, step by step, so you can follow the logic with real numbers.
4. Source citation — the specific document and authority the formula is drawn from, with the last verified date.

This means you can take the result from a FiscalCalc calculator, open the cited source document, and verify the formula independently. If your lender's quote differs from the calculator result, the formula is the starting point for understanding why.

How and when formulas are updated

FiscalCalc runs a full formula review every January, timed to align with the IRS's annual publication of updated tax figures and the CFPB's regulatory calendar. The review covers:

• Federal income tax brackets and standard deduction amounts (IRS Revenue Procedure, published each fall for the following tax year)
• 401(k), IRA, and HSA contribution limits (IRS cost-of-living adjustments, published in October/November)
• Social Security wage base and withholding rate (SSA announcement, published in October)
• CFPB qualified mortgage thresholds and debt-to-income guidelines
• Investopedia formula documentation for investment and savings calculators

The update date for each calculator is noted in its source citation section. You will always see when the formula was last reviewed.

Mid-year changes: If the IRS or CFPB publishes a significant mid-year update that affects a formula (uncommon, but it occurs), we update the affected calculator and flag the change in the source citation. Formulas are not on a fixed schedule — they are updated whenever the underlying source changes materially.

How calculations run

Every FiscalCalc calculator runs entirely in your browser using JavaScript. When you enter inputs and click calculate:

• The calculation executes locally on your device.
• No inputs are transmitted to FiscalCalc's servers or any third party.
• No inputs are stored in a database, logged, or associated with your session.
• When you close the tab, the data is gone.

This is not a privacy policy claim — it is an architectural fact. Client-side JavaScript has no mechanism to transmit your inputs unless we explicitly build one in. We have not. The formula runs locally; the result appears locally. Nothing leaves your browser.

We display advertising through Google AdSense. Ad targeting is based on the page content (a mortgage calculator page, a salary calculator page) — not on the numbers you enter. Google AdSense does not have access to calculator inputs.

What these calculators are — and are not

FiscalCalc calculators are educational tools. They apply standardized formulas to user-provided inputs to produce estimates. They are designed for one purpose: to help you understand the math behind a financial decision before you make it.

They are not:

• Personalized financial advice. Results do not account for your full financial picture, tax situation, credit profile, or local regulations.
• Lender quotes. A mortgage calculator result is not a loan offer. Lenders apply their own rate sheets, origination fees, and underwriting criteria that a standardized formula cannot replicate.
• Tax filings. Tax bracket calculators use federal marginal rates and do not account for state income taxes, itemized deductions, credits, or filing edge cases.
• Investment projections with guaranteed returns. Retirement and investment calculators use user-provided return assumptions. Actual returns vary.

The goal of every FiscalCalc result is to give you a number you understand — one you can verify, question, and use to negotiate. Not one you have to accept on faith.

Where state-specific data comes from

FiscalCalc's state calculator pages display numbers specific to each U.S. state — median household income, median home price, state income tax rate, and more. Each field is sourced from a named government or research authority and updated on a defined schedule.

State data is reviewed and updated on a defined annual schedule: income each September (Census ACS release), tax rates each January (Tax Foundation), and home prices quarterly. The data version used is documented in the site's internal source registry and in each calculator page's metrics footnotes.

How to report a formula error

If you believe a FiscalCalc formula produces an incorrect result — or if a source document has been updated and the calculator has not yet reflected the change — email hello@fiscalcalcs.com with:

• The calculator name and URL
• The specific result you believe is incorrect
• The source or calculation showing what the correct result should be

We verify every report against the primary source. If the formula is wrong, we publish a correction — typically within 48 hours. If the formula is correct and the discrepancy is explained by an assumption difference (for example, a lender applying a different compounding convention), we document that difference in the formula section.

There is no form. Email only. Every report is read and answered.