About Us

100tool.online is an independent website that publishes free, easy-to-use cost calculators for people in the United States. We cover insurance, loans, taxes, salary, savings, business and basic health numbers so you can estimate a cost before you talk to a provider.

Our mission

Prices for insurance, credit and taxes are often hidden until you apply. We believe a clear estimate, a plain-English explanation and an honest note about limits help people make calmer financial decisions.

What we publish

Right now the site offers 22 calculators in six categories. Each page includes the calculator, a description of the formula, a worked example, practical tips and answers to common questions.

How we keep it accurate

We use standard published formulas such as loan amortization and compound growth, and 2025 US federal tax brackets. Assumptions for insurance cost are based on broad market averages and are labelled as estimates. We review the tools regularly. Read the details on our methodology and editorial policy pages.

Independence and funding

The site is free to use and is supported by advertising. Ads never change the numbers you see. We do not sell personal data, and calculator inputs never leave your browser.

Contact

Found an error or have a suggestion? Email contact@100tool.online.