# CalcFYI

> Comprehensive online calculator reference for students, professionals, and everyday users. Covers calculators across categories (financial, health, math, science, conversion, date/time), formula cards with step-by-step derivations, calculator comparisons, real-world scenarios, glossary, and in-depth guides. 15 languages supported.

## Data Scope
- Calculators organized by category (financial, health, math, science, conversion, date/time)
- Formula cards with mathematical notation, derivations, and applications
- Calculator comparisons — when to use which calculator
- Real-world scenarios with worked examples using calculators
- Calculation glossary with mathematical and financial terminology
- In-depth guides organized by series

## URL Patterns
- Append `.md` to any URL for plain-text markdown format.
- i18n: URL prefix `/{lang}` for non-English (ko, ja, zh-hans, es, fr, de, pt, ru, vi, tr, ar, hi, th, id).
- `/category/` — Browse calculator categories (e.g. `/category/`)
- `/category/{slug}/` — Category detail with calculators (e.g. `/category/financial/`)
- `/calculator/{slug}/` — Calculator tool (e.g. `/calculator/compound-interest/`)
- `/glossary/` — Calculation glossary (e.g. `/glossary/`)
- `/glossary/{slug}/` — Glossary term detail (e.g. `/glossary/compound-interest/`)
- `/guide/` — In-depth guides (e.g. `/guide/`)
- `/guide/{series}/` — Guide series (e.g. `/guide/financial-literacy/`)
- `/guide/{series}/{slug}/` — Guide detail (e.g. `/guide/financial-literacy/understanding-apr/`)
- `/formula/` — Formula cards (e.g. `/formula/`)
- `/formula/{slug}/` — Formula card detail (e.g. `/formula/pythagorean-theorem/`)
- `/compare/` — Calculator comparisons (e.g. `/compare/`)
- `/compare/{slug}/` — Comparison detail (e.g. `/compare/simple-vs-compound-interest/`)
- `/scenario/` — Real-world scenarios (e.g. `/scenario/`)
- `/scenario/{slug}/` — Scenario detail (e.g. `/scenario/mortgage-refinancing/`)
- `/search/` — Search calculators, formulas, glossary (e.g. `/search/?q=mortgage`)

## Calculators
- [All Categories](https://calcfyi.com/category/)
- [Calculator Comparisons](https://calcfyi.com/compare/)
- [Real-World Scenarios](https://calcfyi.com/scenario/)

## Reference
- [Formula Cards](https://calcfyi.com/formula/)
- [Glossary](https://calcfyi.com/glossary/)
- [Guides](https://calcfyi.com/guide/)

## Embed Widget
- [CalcFYI Widget Docs](https://widget.calcfyi.com)
- [calcfyi-embed on npm](https://www.npmjs.com/package/calcfyi-embed)
- [calcfyi-embed on GitHub](https://github.com/fyipedia/calcfyi-embed)

## REST API

Free REST API. No authentication required. JSON responses. CORS enabled.

| Method | Endpoint | Description |
|--------|----------|-------------|
| GET | `/api/v1/categories/` | Calculator categories |
| GET | `/api/v1/categories/{slug}/` | Category detail |
| GET | `/api/v1/calculators/` | All calculators |
| GET | `/api/v1/calculators/{slug}/` | Calculator detail |
| GET | `/api/v1/glossary/` | Glossary terms |
| GET | `/api/v1/guides/` | Guide articles |
| GET | `/api/v1/formulas/` | Formula cards |
| GET | `/api/v1/comparisons/` | Calculator comparisons |
| GET | `/api/v1/scenarios/` | Real-world scenarios |
| GET | `/api/v1/faqs/` | FAQs |
| GET | `/api/v1/stats/` | Site statistics |

```bash
curl -s "https://calcfyi.com/api/v1/calculators/"
```

[API Docs](https://calcfyi.com/developers/) · [OpenAPI Spec](https://calcfyi.com/api/openapi.json)

## Developer Tools
- **PyPI**: `pip install calcfyi` — [calcfyi](https://pypi.org/project/calcfyi/) — Online calculators — financial, health and math API client
- **Embed Widget**: [calcfyi-embed](https://widget.calcfyi.com)

## Guide FYI Family

Part of [FYIPedia](https://fyipedia.com) developer tools ecosystem.
- [SalaryFYI](https://salaryfyi.com) — Salary comparison, tax calculators, 36 countries
- [UnivFYI](https://univfyi.com) — University rankings, programs, admissions
- [BoardGameFYI](https://boardgamefyi.com) — Board games, rules, reviews, recommendations

## Full Index
- [Full content index](https://calcfyi.com/llms-full.txt)
- [XML Sitemap](https://calcfyi.com/sitemap.xml)