Henry

Each calculator uses a standard, published formula. Money tools follow common lending and IRS methods. Health tools follow CDC and NIH guidance.

Before a calculator goes live, I test it against worked examples and compare the results with other trusted sources. When rules change, like tax limits each year, I update the numbers.

If you spot a mistake, please tell me through the contact page. I read every message.

I am not a licensed financial advisor, accountant, doctor or dietitian. The calculators and guides are for general information and learning.

For big decisions about money, health or legal matters, please talk with a qualified professional who knows your situation. See our disclaimer and editorial policy.