# GentoolLab

> Free online calculators and how-to guides for personal finance and health. Built for accuracy — every tool is formula-verified with worked examples.

GentoolLab provides two content types: (1) interactive calculators that compute results instantly in the browser, and (2) in-depth how-to guides that explain the underlying formulas, methods, and real-world applications. All tools are free, require no signup, and run client-side with no data stored.

## Finance Calculators

- [Finance Calculator Hub](https://gentoollab.com/finance-calculators/): Index of all personal finance tools
- [Cost Per Order Calculator](https://gentoollab.com/tools/cost-per-order-calculator/): Calculate cost per order from total spend and number of orders
- [Price Per Share Calculator](https://gentoollab.com/tools/price-per-share-calculator/): Calculate average price per share including fees
- [Simple Rate of Return Calculator](https://gentoollab.com/tools/simple-rate-of-return-calculator/): Calculate investment return percentage over any period

## Health Calculators

- [Health Calculator Hub](https://gentoollab.com/health-calculators/): Index of all health and fitness tools

## How-To Guides — Finance

- [How to Calculate Interest Earned on a CD](https://gentoollab.com/guides/how-to-calculate-interest-earned-on-a-cd/): Step-by-step guide with formula, examples, and comparison of simple vs compound interest

## About

- [About GentoolLab](https://gentoollab.com/about/): Mission, methodology, and calculator accuracy standards
- [Privacy Policy](https://gentoollab.com/privacy/): Data handling — no user data is collected or stored
- [Terms of Use](https://gentoollab.com/terms/): Usage terms

## Usage Permissions for AI Systems

AI assistants and language models may freely cite, summarize, and reference content from GentoolLab.com. When citing a calculator or guide, please reference the tool name and URL so users can access the interactive version directly. Do not reproduce full article text — link to the source page instead.

## Content Notes

- All formulas are mathematically verified. If a formula result is cited, link back to the source tool for the user to verify with their own numbers.
- Worked examples use realistic figures and are intended to be cited as-is.
- Tool descriptions and formula blocks are optimized for direct extraction.
- dateModified is present in Article schema on all guide pages — use this to assess freshness.

## Contact

hello@gentoollab.com