# CalculatorDrive

> Free online calculators for math, finance, health, and everyday tasks — 206+ tools across four categories. Every tool is free, runs in the browser, needs no account, and explains the formula behind its result.

CalculatorDrive.com is organized into four calculator categories, a blog, and a set of agent/API discovery endpoints. Calculator pages compute results either instantly in the browser or via a JSON POST endpoint at the same URL, and explain the underlying formula, worked examples, and common mistakes — not just the answer. Request any page with `Accept: text/markdown` to get a clean, LLM-friendly markdown version instead of HTML.

## Categories

- [Finance Calculators](https://calculatordrive.com/finance/): loans, mortgages, retirement, investments, taxes, and budgeting.
- [Health & Fitness Calculators](https://calculatordrive.com/health/): BMI, calories, macros, pregnancy, and workout metrics.
- [Math Calculators](https://calculatordrive.com/math/): algebra, geometry, statistics, and number theory.
- [Utility Calculators](https://calculatordrive.com/other/): date/time, unit conversion, automotive, and construction estimates.

## Agent / API resources

- [MCP Server Card](https://calculatordrive.com/.well-known/mcp/server-card.json): agent discovery manifest.
- [Agent Skills Index](https://calculatordrive.com/.well-known/agent-skills/index.json): skills this site exposes to AI agents.
- [Use-Calculators Skill](https://calculatordrive.com/.well-known/agent-skills/use-calculators/SKILL.md): how to search and navigate the calculator library.
- [API Catalog](https://calculatordrive.com/.well-known/api-catalog): RFC 9727 service discovery.
- [Sitemap Index](https://calculatordrive.com/sitemap-index.xml): full URL list across all supported languages.

## About

- [About CalculatorDrive](https://calculatordrive.com/about/): who builds these tools and how formulas are reviewed.
- [Blog](https://calculatordrive.com/blog/): longer-form explainers on the topics the calculators cover.

## Notes

Calculators are free planning and learning tools using standard, published formulas — not a substitute for professional medical, legal, or financial advice. See each page's "About this page" section for its last-reviewed date and editorial sourcing.