Sources and Methodology
How Irish Calculators approaches official sources, assumptions, calculator logic, annual updates, and accuracy checks.
Our approach to sources
Irish Calculators aims to start from official or public Irish sources, then convert complex rules into practical calculator inputs, outputs, notes, and guide explanations.
Some tools require simplified assumptions because real-life cases can depend on details that a short calculator cannot fully capture. Those assumptions should be visible on the calculator page, not hidden behind the final number.
Where figures come from
Revenue
Tax, PAYE, USC, credits, reliefs, VAT, CGT, property tax, and related Irish tax information.
revenue.ie ↗Department of Social Protection
Current PRSI classes, contribution rates, credits, thresholds, and social insurance guidance.
gov.ie / Social Protection ↗Citizens Information
Employment, redundancy, tax, consumer rights, public schemes, and plain-English public information.
citizensinformation.ie ↗Central Bank of Ireland
Mortgage lending rules, financial regulation context, and consumer-focused financial information.
centralbank.ie ↗Official scheme pages
Help to Buy, First Home Scheme, and other official government or scheme-specific sources.
gov.ie ↗Editorial responsibility and date labels
Calculator and guide content is published by the Irish Calculators editorial team. This identifies the organisation responsible for the page; it does not claim that a named accountant, tax adviser, solicitor or financial adviser has reviewed it unless that person and their relevant credentials are explicitly shown.
Last reviewed means the content was deliberately checked against the linked official sources on that date. If no explicit review has been recorded, a guide shows its genuine Last updated date instead. A software update alone is not presented as an editorial review.
Calculator examples are generated from documented calculation rules. Editorial pages explain the important assumptions, exclusions and source hierarchy so users can understand how a result or summary was produced.
Methodology principles
Every calculator should be easy to use but honest about what is simplified.
Use clear inputs
Fields should match what a normal user can reasonably know without needing a spreadsheet.
Show useful outputs
Results should include the headline number and a breakdown where it helps users understand the calculation.
Explain assumptions
Methodology notes should say what is included, excluded, and likely to vary in real life.
Link guidance
Calculator pages should connect users to guides, official sources, and related tools for the next decision.
How we handle updates
Calculator assumptions and rate tables are reviewed after the annual Budget, when Revenue publishes updated thresholds, and when major scheme or employment rules change. Guide content should be checked when Citizens Information or official scheme pages change the underlying rules.
If you find a figure that looks wrong, send us the page URL and the source you are checking against through the contact page.
The 2026 salary example assumptions were checked on 15 July 2026 against Revenue’s tax and USC tables and the Department of Social Protection’s Class A PRSI rates. Other pages carry their own explicit review date or genuine last-updated date.
Known limits
A useful calculator is still only a first estimate.
- Tax calculators may not cover every relief, exemption, unusual income type, residency issue, or filing situation.
- Mortgage calculators cannot guarantee lender approval or exact treatment of income, costs, dependants, credit history, or stress testing.
- Employment calculators may not cover every contract term, company policy, sector rule, dispute, or legal interpretation.
- Guide content may summarise complex official rules and should be checked against official sources before important decisions.
Found something outdated?
If a threshold, scheme rule, source note, or calculator assumption looks wrong, send the page URL and the correction source.