TariffCostCalc.com aims to publish helpful, verifiable, and transparent customs-cost information. Our pages prioritize government and customs authority resources where possible.
Research and sourcing
Regulatory claims are checked against customs agencies, primary legislation, official tariff schedules, or government guidance. Secondary sources may help explain implementation but do not supersede official law.
Formula validation
We document the inputs and arithmetic behind tools. Where rules depend on classification, import date, eligibility, or exceptions, we expose assumptions instead of claiming all-in certainty.
Corrections and revisions
Trade rules may change without notice. Articles and calculators are reviewed when significant rule changes are identified. Dates in content indicate the last substantive review, not a guarantee that every tariff rate is current.
Updated November 14, 2026. These policies explain how the website publishes, uses and qualifies informational calculator content.
Our standard for a useful calculator page
A calculator page should answer the user’s question, display understandable field labels and show the formula or calculation logic in plain language. It should explain important limitations, identify where government law or carrier-specific terms affect the result, and offer worked examples that users can reproduce. Adding more words without answering those questions is not a quality improvement.
We review calculators for arithmetic, input validation, mobile usability, clear results and misleading defaults. Pages should not use a tariff percentage merely because that number looks plausible in a search result. When an exact duty is not available, the rate remains an assumption that visitors must verify.
How sources are chosen and cited
Our highest-priority references for legal customs claims are legislation, regulations, official government notices, customs agencies and published national tariff schedules. We may refer to recognized trade institutions for commercial terms, such as the International Chamber of Commerce’s Incoterms guidance. Secondary commentary helps identify questions but does not overrule primary law.
Where rules depend on a date, the page should identify that effective period and any known transition. A source link supports only the particular issue it covers, not every future amendment. Readers should use official sources applicable to their own product and entry date rather than rely on a historical worked example.
Distinguishing examples from real tariffs
Worked examples are made to demonstrate arithmetic and may use hypothetical goods values, duty rates, shipping quotes and margins. A US tariff stacking example using a 25% additional duty is not a statement that every product from any named country faces that rate. Likewise, a default 20% EU VAT example is not a declaration of the correct rate in each EU Member State.
We aim to label examples clearly, keep user-entered assumptions editable and separate fees from duty and taxes. We do not publish a definitive country-to-country duty result based only on origin and destination. Full national HS/HTS classification and legal measures are usually required.
Fact checking and formula review
Before publishing significant customs content, we check the effective date, scope, exceptions and principal formula against reliable current sources. For code, we examine the input constraints, zero and invalid cases, unit conversions, result labels and whether amounts can be counted twice. Where a real-browser or external delivery test has not been performed, it should not be described as completed.
Periodically, a law can change after content was last updated. A review date indicates the latest substantive revision of the page, not continuous real-time monitoring. We may correct or replace older information when the relevant authority publishes an updated rule.
Corrections and reader feedback
If a reader finds an error, we encourage a report with the URL, the question or calculation, a reproducible set of inputs, and an authoritative citation where applicable. We assess whether the reported issue is arithmetic, unclear wording, outdated legal information or a difference in assumptions. Significant corrections may warrant changing both explanatory text and the underlying calculator.
Contact us at contact@tariffcostcalc.com. We do not request identifying customs entry credentials or confidential financial account details to investigate a normal calculation issue.
Editorial review and commercial relationships
Commercial arrangements, sponsorships and affiliate commissions must not change a government rate or the result of a calculation. If the website later offers paid referrals, advertising or sponsored material, those relationships should be identified clearly. A recommendation to compare a freight quote is not itself a promise of price, suitability or service availability.
We strive to distinguish independent educational tools from paid services offered by third parties. Users should read the provider’s current terms and service coverage before purchasing shipping, financial or tax services.
Frequently asked questions
Editorial review and corrections
Why do sources sometimes refer to different years?
Different fees and customs rules have different effective dates. The applicable date must match the entry or transaction being evaluated.
Can a reader submit a correction?
Yes. Include the page URL, the source and what needs changing.
Commercial separation
If affiliate links or advertisements are introduced, they will not control formula outputs. We do not sell preferential placement inside numerical results.