Editorial Policy

Calculatormatics.com publishes calculators that return numbers people rely on for real decisions — mortgage payments, tax liability, health metrics, retirement projections. This page explains how we research, review, update, and correct that content so you know exactly what stands behind every result.

How We Research Formulas and Data

Every calculator is built from a publicly-documented formula taken from an authoritative source. We do not invent methods, reverse-engineer competitors, or use approximations where an exact formula exists. Primary sources by topic:

• US tax data — IRS.gov for federal brackets, standard deductions, FICA rates, and retirement contribution limits (401(k), IRA, Roth IRA, HSA).
• UK tax data — HMRC / gov.uk for PAYE, National Insurance, SDLT, ISA allowances, and pension rules.
• India tax data — The Income Tax Department of India for old vs. new regime slabs, plus the Union Budget for annual updates. EPFO, NPS Trust, and India Post for retirement-scheme rates.
• EU/UK financial regulators — European Commission for VAT rates, the Bank of England and ECB for benchmark rates.
• Health formulas — published medical formulas with the named originator: Mifflin–St Jeor (BMR), US Navy method (body fat), Karvonen (heart-rate zones), Naegele’s rule (due date), Epley (one-rep max), Devine / Robinson / Miller / Hamwi (ideal weight). WHO categories for BMI interpretation.
• Physical constants and unit definitions — BIPM / SI for the exact definitions of the meter, kilogram, second, and derived units.

How We Review Content

Each calculator goes through three checks before publication and whenever the underlying data changes:

1. Formula verification. The math shown on the page is tested against worked examples from the source document (IRS Publication, HMRC guidance note, or the original peer-reviewed paper for medical formulas) until results match to the cent or to appropriate decimal precision.
2. Cross-check against a second authoritative calculator where one exists (for example, the IRS tax tables, HMRC’s PAYE checker, or a published journal table). Any discrepancy is investigated before the calculator goes live.
3. Content review. The surrounding educational content — formulas, worked examples, FAQs, and disclaimers — is reviewed for accuracy, clarity, and appropriate caveats (especially for YMYL topics: financial and health).

How and When Data Is Updated

Tax rates, contribution limits, and benchmark interest rates change every year. Our update schedule:

• US tax data — updated every January, after the IRS publishes the following year’s brackets and limits (typically October/November).
• UK tax data — updated every April, when the new UK tax year begins (April 6). Covers PAYE bands, NI thresholds, ISA allowance, SDLT.
• India tax data — updated in March, after the Union Budget is presented in February.
• EU/UK VAT — reviewed every January for any announced rate changes.
• Savings scheme rates (PPF, Sukanya Samriddhi, NPS, etc.) — reviewed quarterly, since the government announces rates each quarter.
• Currency exchange rates — cached daily from an exchange-rate API; the currency converter shows the effective date.

Each data file in our code repository carries a lastUpdated date and a reviewBy deadline. If you see a calculator using older data than the latest announcement, please tell us — see corrections below.

Disclaimers and Professional Advice

Every financial and health calculator includes a disclaimer that the result is an estimate for informational purposes, not personalized financial, legal, medical, or tax advice. See our Disclaimer for the full scope and limitations. For decisions with real money or health consequences, consult a licensed professional.

Corrections Policy

If you find an error — wrong formula, outdated tax bracket, mismatched result compared to an official source — please contact us via the Contact page with the page URL and the discrepancy. We treat correction requests as priority work. Verified errors are fixed within 72 hours; minor phrasing or clarity improvements are batched into the next routine review.

Transparency

We earn revenue from advertising, not from selling user data. Cloudflare Web Analytics is cookie-free and enabled by default; third-party advertising scripts load only after you accept cookies. We do not have a premium tier, paywall, or gated content — every calculator and every word of supporting content is free to use. See our Privacy Policy for what we do and do not collect.