Editorial policy

1. Purpose of our content

HoldingCost publishes calculators, guides, and glossary entries to help people understand the financial mathematics behind everyday decisions. The content is educational, not advisory. We aim for our calculators to be the most accurate, transparent, and reproducible free tools on the open web — and for our supporting content to teach the underlying concepts so the numbers are meaningful, not just present.

2. Globally neutral by design

Every calculator, guide, and glossary entry on HoldingCost is written to be globally neutral. We use generic currency placeholders ($X) and refer to "many jurisdictions" rather than naming specific countries. Tax rates, withholding rules, regulator thresholds, and consumer-credit caps differ by country, state, and over time — and our calculators do not encode any of them. This is a deliberate constraint, not a limitation: it forces our methodology to be portable and our editorial voice to be teach-the-concept rather than recite-this-rate.

3. No personal advice

Nothing on this site is personal financial advice. We do not know your circumstances, and our content is not tailored to them. Our content can help you reason about a decision, but the decision itself should be made with a qualified, licensed professional in your jurisdiction. The full position is in our disclaimer.

4. How we research and review formulas

Each calculator is built around a documented mathematical engine. The formulas are derived from canonical references (textbook amortisation, compound-interest standards, EOQ formulations, and the like), implemented in TypeScript using a fixed-point decimal arithmetic library to eliminate rounding drift, and unit-tested to 100% branch coverage against known-answer reference values. Financially critical engines (mortgages, debt simulations, capital gains) carry an additional precision-test layer that exercises large-number, small-number, zero-rate, and rounding-consistency cases.

Each calculator page also surfaces a methodology block that lists the engine version, the assumptions made, the formula used, and the sources we relied on. The engine code itself is open: anyone can read what the calculator is doing, and any change to the formula bumps the engine version stamped on every result.

5. How we choose defaults

The pre-filled values in calculator inputs are illustrative, not advisory. We choose defaults that are recognisable to a typical reader, that produce a meaningful (non-degenerate) result, and that do not anchor the reader toward any specific product or provider. Defaults are reviewed periodically against the calculator's domain — for example, illustrative interest rates are kept inside a plausible range so the result is informative rather than misleading.

6. Review cadence

Every guide and glossary entry carries a "last reviewed" date in its metadata. We run a freshness check that flags any item over 90 days stale, so the editorial backlog reflects what genuinely needs revisiting rather than churn. Calculator engines are versioned independently — a formula change bumps the engine version, which appears on the calculator page and in any shared scenario URL.

7. Sources

We rely on primary sources: standards bodies, central banks, academic finance and operations-research literature, and the canonical mathematical references for each engine. We avoid citing other commercial calculators as sources, and we do not republish content from other publishers. Where a guide explains a concept, the underlying derivation is from a primary reference, not a secondary one.

8. Commercial independence

HoldingCost's revenue model (display advertising, when live; see how we make money) is architecturally separated from our editorial output. The advertising layer of the codebase cannot read calculator inputs or influence calculator outputs — this separation is enforced by an architectural boundary between our advertising and calculation systems. No advertiser, sponsor, or affiliate has editorial influence over which calculators we build, what defaults we choose, what guides we publish, or how the methodology section is worded. We do not accept paid placements in calculator results, guide content, or glossary definitions.

9. AI-assisted content

AI tools may be used as a drafting aid for prose. Every published article, guide, and glossary entry is reviewed by a human editor and validated against primary sources before publication. Calculator outputs are computed by deterministic, version-controlled engines — never generated by AI. The engine code is open and the formulas are documented in the methodology block on each calculator page.

10. Error correction

If you spot an error in a calculator result, a guide, or a glossary entry, we want to know. See our contact page for how to reach us. We aim to acknowledge corrections within 5 business days and, where the error affects a calculation, bump the engine version when the fix ships so prior shared scenarios surface the correction.