Sources
This page lists every external source used by Toolivaro tools and editorial content (PROMPT.md §9). Each entry records the owner, the URL, the version or effective date when known, and the date the source was last checked. Sources are reviewed on a recurring schedule; stale entries are removed or updated.
| Source | Owner | Version | Last checked | Used by |
|---|---|---|---|---|
| Gross Profit Margin: Formula and What It Tells You | Investopedia | Article revision 2025 | 2026-07-15 | Profit Margin Calculator, Gross Profit Calculator |
| Margin vs Markup | Corporate Finance Institute (CFI) | 2025 revision | 2026-07-15 | Profit Margin Calculator, Markup Calculator, Discount Calculator |
| Break-even point analysis | U.S. Small Business Administration | — | 2026-07-15 | Break-Even Calculator |
| How much paint do I need? | Sherwin-Williams | — | 2026-07-15 | Paint Calculator |
| Pricing — payment processing fees | Stripe | — | 2026-08-05 | Payment-Processing Fee Calculator |
| Burn Rate | Corporate Finance Institute (CFI) | — | 2026-08-05 | Cash Runway Calculator |
| Portable Network Graphics (PNG) Specification | W3C | PNG 3.0 (Candidate Recommendation 2025) | 2026-08-05 | Image Resizer, Image Compressor, JPG, PNG & WebP Converter |
| WebP — An image format for the web | — | 2026-08-05 | Image Resizer, Image Compressor, JPG, PNG & WebP Converter | |
| JPEG — The JPEG Standard (ISO/IEC 10918) | JPEG Committee | — | 2026-08-05 | Image Resizer, Image Compressor, JPG, PNG & WebP Converter |
| ISO 8601 — Date and time format | ISO | ISO 8601-1:2019 | 2026-08-05 | Date Difference Calculator, Business Days Calculator |
| Pricing & Business Model | SCORE | — | 2026-08-05 | Billable Hourly Rate Calculator |
| Gravel Calculator — volume, weight and coverage | CalculatorSoup | — | 2026-08-05 | Gravel Calculator |
| Time zone database (tz database / IANA) | IANA | tzdata 2026a | 2026-07-15 | Time Zone Converter, Meeting Overlap Planner |
| Introducing JSON | JSON.org | — | 2026-07-15 | JSON Formatter & Validator, JSON Minifier |
| RFC 4180 — Common Format and MIME Type for CSV Files | IETF | RFC 4180 (October 2005) | 2026-07-15 | CSV to JSON Converter, JSON to CSV Converter |
| RFC 4648 — The Base16, Base32, and Base64 Data Encodings | IETF | RFC 4648 (October 2006) | 2026-07-15 | Base64 Encoder & Decoder |
| Concrete calculator (bag yields) | Quikrete | — | 2026-07-15 | Concrete Calculator |
| Tile installation resources | Tile Council of North America (TCNA) | — | 2026-07-15 | Tile Calculator |
| Flooring installation and care resources | National Wood Flooring Association (NWFA) | — | 2026-07-15 | Flooring Calculator |
| Counting tokens | Anthropic | — | 2026-08-05 | AI Token Counter |
| API pricing | Anthropic | — | 2026-08-05 | AI Token Counter |
| RegExp — JavaScript reference | MDN Web Docs | — | 2026-08-05 | Regex Tester |
| GNU Diffutils Manual | GNU Project | — | 2026-08-05 | Text Diff Checker |
| RFC 3339 — Date and Time on the Internet: Timestamps | IETF | RFC 3339 (July 2002) | 2026-08-05 | Unix Timestamp Converter |
| RFC 4122 — A Universally Unique IDentifier (UUID) URN Namespace | IETF | RFC 4122 (July 2005) | 2026-08-05 | UUID Generator |
| Percentage Change: Formula and Examples | Investopedia | Article revision 2025 | 2026-08-11 | Percentage Calculator |
| Percent problems — Arithmetic essentials | Khan Academy | Course material | 2026-08-11 | Percentage Calculator |
| SI Brochure — The International System of Units (9th edition) | BIPM / NIST | SI Brochure, 9th edition (2019) | 2026-08-11 | Data Size Converter, Unit Converter |
| NIST Handbook 44 — Specifications, Tolerances, and Other Technical Requirements | NIST | Handbook 44, 2026 edition | 2026-08-11 | Unit Converter |
| Guide for the Use of the International System of Units (SI) | NIST | SP 811 (2008 edition) | 2026-08-12 | — |
| ISO 80000-1 — Quantities and units — Part 1: General | ISO | 2nd edition (2022) | 2026-08-12 | — |
| IEEE 754 — Standard for Floating-Point Arithmetic | IEEE | IEEE 754-2019 | 2026-08-12 | — |
| ECMAScript Internationalization API Specification | Ecma International | — | 2026-08-12 | — |
| Body mass index (BMI) | World Health Organization | — | 2026-08-11 | BMI Calculator |
| About Adult BMI | U.S. Centers for Disease Control and Prevention | — | 2026-08-11 | BMI Calculator |
| Gregorian calendar | Encyclopaedia Britannica | Encyclopedia entry | 2026-08-11 | Age Calculator |
| What is amortization and how could it affect my auto loan? | U.S. Consumer Financial Protection Bureau | — | 2026-08-11 | Loan Amortization Calculator |
| Amortization — formula and schedule | Investopedia | Article revision 2025 | 2026-08-11 | Loan Amortization Calculator |
| Compound Interest Calculator | U.S. Securities and Exchange Commission (investor.gov) | — | 2026-08-11 | Compound Interest Calculator |
| The Power of Compound Interest: Calculations and Examples | Investopedia | Article revision 2025 | 2026-08-11 | Compound Interest Calculator |
| encodeURIComponent() — JavaScript reference | MDN Web Docs | — | 2026-08-11 | URL Encoder / Decoder |
| decodeURIComponent() — JavaScript reference | MDN Web Docs | — | 2026-08-11 | URL Encoder / Decoder |
| CSS Color Module Level 4 — hex notation and rgb() | W3C | W3C Recommendation (2025) | 2026-08-11 | Hex to RGB Converter |
| BigInt — JavaScript reference | MDN Web Docs | — | 2026-08-11 | Number Base Converter |
| NIST SP 800-63B — Digital Identity Guidelines: Authentication | National Institute of Standards and Technology | SP 800-63B-3 | 2026-08-12 | Password Generator, Hash Generator |
| Password Storage Cheat Sheet — password length guidance | OWASP Foundation | — | 2026-08-12 | Password Generator |
| Web Crypto API — crypto.subtle | MDN Web Docs | — | 2026-08-12 | Hash Generator |
| Crypto.getRandomValues() — cryptographically secure random values | MDN Web Docs | — | 2026-08-12 | Password Generator |
| RFC 7519 — JSON Web Token (JWT) | IETF | — | 2026-08-12 | JWT Decoder |
| RFC 7515 — JSON Web Signature (JWS) | IETF | — | 2026-08-12 | JWT Decoder |
| crontab(5) — cron table file format | OpenBSD Manual Pages | — | 2026-08-12 | Cron Builder |
External sources are referenced for verification and explanation. Their content is outside Toolivaro's control; each source is listed here with the date it was last checked so readers can assess freshness.