About

This site is a collection of single-purpose calculators. Each one does one job, loads fast, and shows the formula it uses so you can check the result yourself.

How the calculators are built

Every calculator runs entirely in your browser. No data is sent to a server, which keeps financial and personal figures on your own device and makes the tools fast enough to update as you type.

How we handle the formulas

Each calculator page states the formula, defines every variable with its unit, lists the assumptions behind the result, and walks through a worked example using the default inputs. If a number looks wrong, you can trace exactly where it came from.

Accuracy and limitations

These tools are for planning and estimation. Real-world results depend on factors a calculator cannot see — local tax rules, your lender's specific terms, material prices in your area. Nothing here is financial, tax, legal or professional advice.

Contact

Found an error, or want a calculator that does not exist yet? Feedback is welcome — see the privacy page for contact details.