How we research, build, review, and maintain the financial calculators and guides on TheMetricApp.
Our mission is to provide free, accurate, and transparent financial calculators that help freelancers, gig workers, sellers, and small business owners make informed financial decisions. We hold ourselves to high standards of accuracy, transparency, and user privacy — and this page explains exactly how we achieve that.
Every calculator is built from official sources — IRS publications, HMRC guidance, platform fee schedules, and government data. Formulas are verified against real-world examples before publishing.
Tax brackets, fee structures, and financial regulations change. We audit all calculators annually (and immediately when major changes occur) to keep every tool current. Each page displays its last updated date.
Every calculator and its accompanying educational content is reviewed by a second team member before publishing. We check calculation logic, formula accuracy, and factual claims independently.
All calculations run entirely in your browser. No numbers, inputs, or results are sent to our servers. We do not collect, store, or sell user financial data.
We clearly state when a calculator is an estimate. We cite our sources, disclose our methodology, and recommend consulting a qualified professional for tax, legal, or financial advice.
TheMetricApp is supported by non-intrusive advertising. Every calculator is and will remain 100% free — no paywalls, no sign-ups, no premium tiers.
We identify the primary official source for each calculator's data — IRS.gov for US tax rates, HMRC for UK rates, platform help centers for fee schedules. We cross-reference multiple sources before writing any formula.
The calculation logic is built and tested against known examples. For tax calculators, we verify against IRS worksheets. For fee calculators, we verify against platform documentation and real transaction examples.
We write clear, jargon-free explanations of how the calculator works, what the formulas mean, and how to interpret results. Content includes worked examples, comparison tables, and real-life scenarios.
A second team member reviews the calculator logic, checks all formulas, fact-checks the educational content, and verifies all source links. Any discrepancies are resolved before publishing.
We add structured data (JSON-LD) including WebApplication, FAQPage, and BreadcrumbList schemas to help search engines understand and surface our content accurately.
We monitor official sources for changes to tax rates, fee structures, and regulations. When changes occur, we update the affected calculators within 30 days and update the 'Last Updated' date on the page.
TheMetricApp is built and maintained by a team of financial professionals with backgrounds in accounting, tax preparation, financial planning, e-commerce, and the gig economy. Each piece of content is written by a subject-matter expert and reviewed by a second team member before publication.
Meet our full team of experts →
Disclaimer: TheMetricApp team members are not licensed CPAs, tax attorneys, or registered financial advisors. Our calculators are for estimation and educational purposes only. Always consult a qualified professional for advice specific to your situation.
We build our calculators from official, publicly available sources. Below are the primary references we use for our most popular calculator categories:
US federal tax brackets, SE tax rates, mileage rates, contribution limits
UK income tax, National Insurance, VAT rates, Self Assessment
Mortgage guidelines, lending standards, consumer finance
Weekly US mortgage rate survey
Payment processing fee schedules
PayPal transaction and merchant fees
FBA fees, referral fees, fulfillment costs
Final value fees, listing fees, managed payments
Listing, transaction, and payment processing fees
Subscription plans, transaction fees, payment processing
Host service fee structure
EV charging costs, solar incentives, energy data
Annual reviews: All calculators are reviewed at the start of each calendar year to incorporate new tax brackets, contribution limits, fee schedule changes, and regulatory updates.
Immediate updates: When a major change occurs mid-year (e.g., IRS announces new mileage rates, a platform changes its fee structure), we update the affected calculator within 30 days of the official announcement.
Corrections: If you find an error in any of our calculators or content, please contact us via our contact page. We take accuracy seriously and will investigate and correct any verified errors promptly.
Last Updated dates: Every calculator page displays the date it was last reviewed or updated. This reflects the most recent verification of the calculation logic and data sources.
TheMetricApp uses AI tools to assist with grammar checking, formatting, and initial research. However, all calculation logic, formulas, and financial data are verified by human team members against official sources before publishing. No calculator output is generated by AI — every formula is hand-coded and tested.
Educational content may be drafted with AI assistance but is always reviewed, fact-checked, and edited by a human team member before publication. We do not publish AI-generated content without human review and verification.
Have a question about our editorial standards?
We welcome feedback, corrections, and suggestions from our users.
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