# WorldCalculators.org

> Free, ad-free, no-tracking international calculators built around one idea: the *same formula gives a different answer in a different country*. BMI thresholds, take-home pay, income tax, mortgages/EMI, VAT/GST, tipping, inflation and 124+ more. Every page opens with a direct Quick Answer, shows side-by-side country comparison tables, cites primary national authorities (WHO, NHS, IRS, HMRC, JASSO, OECD, central banks), and is built as static HTML so the full answer is readable without running JavaScript.

## Core hubs
- [All calculators](https://worldcalculators.org/calculators): Full directory of 124+ calculators across Health, Finance, Math, Conversion and Utility.
- [Calculators by country](https://worldcalculators.org/countries): How standards differ in the US, UK, Japan, China, Canada, Australia and Germany.
- [Learning hub](https://worldcalculators.org/learning): Plain-language explainers on how to calculate things and how different countries teach and standardize math.
- [Methodology & sources](https://worldcalculators.org/methodology): Data sources, authorities cited, review process and update cadence.
- [About](https://worldcalculators.org/about): Mission and editorial approach.
- [Full machine-readable index](https://worldcalculators.org/llms-full.txt): Complete list of every calculator with descriptions.

## Most-cited calculators (country-aware)
- [BMI calculator](https://worldcalculators.org/calculators/bmi): WHO vs Asia-Pacific vs Japan (JASSO) vs China (WGOC) vs Korea thresholds.
- [Paycheck / take-home pay](https://worldcalculators.org/calculators/paycheck): Net pay after tax for the US, UK, Canada and Australia.
- [Income tax calculator](https://worldcalculators.org/calculators/tax): Income tax for the US, UK (incl. National Insurance) and Canada.
- [Mortgage calculator](https://worldcalculators.org/calculators/mortgage): US 30-yr fixed vs UK 2–10yr vs Canada 25-yr terms.
- [VAT / GST calculator](https://worldcalculators.org/calculators/vat-calculator): India GST, UK VAT, Australia GST, Singapore GST — add or remove tax.
- [Tip calculator](https://worldcalculators.org/calculators/tip): Tipping norms across 8+ countries including Japan's no-tip culture.
- [Inflation calculator](https://worldcalculators.org/calculators/inflation): US, UK, EU and Japan CPI — the value of money over time.
- [Compound interest](https://worldcalculators.org/calculators/compound-interest): APY (US) vs AER (UK), daily/monthly/annual compounding.

## Localized & country calculators
- [BMI 計算機 — Japan / JASSO](https://worldcalculators.org/jp/bmi-calculator)
- [BMI Rechner — Germany](https://worldcalculators.org/de/bmi-rechner)
- [Calculateur IMC — France](https://worldcalculators.org/fr/calculateur-imc)
- [India income tax — old vs new regime](https://worldcalculators.org/in/income-tax-calculator)
- [SIP calculator — India](https://worldcalculators.org/in/sip-calculator)
- [UAE salary calculator](https://worldcalculators.org/ae/salary-calculator)
- [UK take-home pay](https://worldcalculators.org/uk/take-home-pay-calculator)
- [Brazil CLT salary](https://worldcalculators.org/br/calculadora-clt)
- [India in-hand salary — new regime FY 2026-27](https://worldcalculators.org/in/in-hand-salary-calculator)
- [UK "after tax" salary pages](https://worldcalculators.org/salary/uk): Take-home for common UK salaries, 2026/27.
- [Germany "brutto netto" pages](https://worldcalculators.org/salary/de): Netto for common German salaries, 2026.
- [India "in-hand salary" pages](https://worldcalculators.org/salary/in): In-hand for common CTCs, FY 2026-27 new regime.

## Tools & data stories
- [Embeddable BMI widget](https://worldcalculators.org/embed): Free multi-standard BMI calculator (WHO/Japan/Asia-Pacific/China) for any site.
- [Dollar vs yen inflation, 1990–2025](https://worldcalculators.org/stories/dollar-vs-yen-inflation): The US dollar lost ~59% of its buying power; the yen ~17%.

## How countries differ (explainers)
- [How countries calculate differently](https://worldcalculators.org/guides/how-countries-calculate-differently)
- [How countries teach math](https://worldcalculators.org/learning/math/how-countries-teach-math)

## GEO / AEO passage chunks (~800 tokens, cl100k_base)
Machine-readable self-contained passages for RAG pipelines and answer engines:
- Index: https://worldcalculators.org/geo-chunks/manifest.json
- AEO array: https://worldcalculators.org/aeo-chunks.json (cl100k_base token counts)
- Stream: https://worldcalculators.org/geo-chunks/chunks.jsonl (newline-delimited JSON)
- Single chunk: https://worldcalculators.org/geo-chunks/c/{id}.json
- Markdown mirror: https://worldcalculators.org/geo-chunks/c/{id}.md
- Agent API catalogue: https://worldcalculators.org/api/v1/manifest.json