Trust & Transparency

Editorial Standards

Our editorial mission

SimplyCalc publishes two types of content: interactive calculators and explanatory articles. Both are held to the same standard — accurate, transparent, and written to help readers understand their financial situation, not to direct them toward any particular product or service.

How calculators are built and verified

Each calculator is built from primary regulatory sources:

  • UK tax calculators: HMRC published rates, National Insurance thresholds, and personal allowance figures for the current tax year.
  • US tax calculators: IRS published federal tax brackets, standard deduction, and FICA rates. State tax uses published effective rate averages.
  • Mortgage calculators: Standard amortisation formula. Results verified against outputs from multiple institutional mortgage calculators.
  • Health calculators: WHO BMI classification standards, Mifflin-St Jeor TDEE formula, and established body fat estimation methods.
  • Currency converter: Live rates from the European Central Bank via Frankfurter.app, updated daily. Fallback to reference rates when the API is unavailable.

All calculators run client-side in the user's browser. No data is transmitted to any server. Results are instantaneous and private.

How articles are researched and written

Articles on SimplyCalc follow a consistent process:

  1. Primary source research: Facts, statistics, and regulatory details are sourced from government bodies, central banks, and peer-reviewed research wherever possible. These sources are cited within the article.
  2. Worked examples: Every article includes at least one worked numerical example to ground abstract concepts in real figures. These are verified against the site's own calculators.
  3. Editorial review: Articles are reviewed for factual accuracy, internal consistency, and reader clarity before publication.
  4. Regional relevance: Where content applies differently across markets, we note the specific country or jurisdiction. Finance law, tax, and mortgage rules vary significantly between the UK, US, Germany, Norway, Australia, and Canada.

Rate and threshold updates

Tax thresholds, NI rates, mortgage rate benchmarks, and similar figures change annually or more frequently. We review and update calculators and articles at the start of each UK tax year (April) and when significant rate changes occur in other markets. The date of last review is shown on each calculator and article page.

Corrections policy

If a calculation or article contains an error, we correct it promptly. Significant corrections are noted in the article with the date of correction. We welcome corrections from readers — if you spot an error, please email hello@simplycalc.io with the page URL and the specific issue.

What we are not

SimplyCalc is not a regulated financial adviser. We are not authorised by the FCA, SEC, or any equivalent body. Content on this site is for general information and educational purposes only. It does not constitute personalised financial, tax, or investment advice. For decisions involving significant sums — mortgages, pension planning, investment allocation — we recommend consulting a qualified independent financial adviser who can take your personal circumstances into account.

Advertising and commercial relationships

SimplyCalc displays advertising through Google AdSense. We do not accept sponsored content, affiliate arrangements with financial providers, or payment to feature or recommend specific products. Advertising revenue does not influence our editorial content. The calculators are free and will remain free.

External sources we rely on

For UK calculations: HMRC published threshold tables (gov.uk), Bank of England Monetary Policy Committee decisions, ONS Consumer Price Index data, PLSA Retirement Living Standards research, and FCA regulatory guidance.

For US calculations: IRS Revenue Procedures (annual tax brackets and standard deductions), Social Security Administration FICA rate tables, Consumer Financial Protection Bureau mortgage data.

For health calculators: World Health Organisation BMI classification reference (2000), Mifflin-St Jeor equation as validated by Frankenfield et al. (2005) in the Journal of the American Dietetic Association, and the Hodgdon and Beckett circumference-based body density equations (1984, Naval Health Research Center).

For currency conversion: European Central Bank reference exchange rates, distributed daily via Frankfurter.app under open data terms.

What we are not

SimplyCalc is not a regulated financial adviser and does not hold authorisation from the FCA, SEC, BaFin, or any other financial regulator. Nothing on this site constitutes personalised financial, tax, investment, or medical advice. For decisions involving significant sums of money or material health implications, please consult a qualified professional who can take your personal circumstances into account. We exist to help you understand your situation and ask better questions — not to replace professional advice.