About CalcNotebook

CalcNotebook is a growing collection of free online calculators and everyday utilities: percentages, dates, loans, health metrics, passwords and more. The goal is simple — the tools people reach for every day, without clutter, pop-ups or sign-up walls.

Our principles

• Fast: every page is static and loads in a fraction of a second, even on slow mobile connections.
• Private: calculations run entirely in your browser. What you type never reaches our servers.
• Honest: each tool explains its formula, its assumptions and its limitations — including when you should ask a professional instead.

How the site is funded

CalcNotebook is free to use and supported by advertising. Ads never influence the results the calculators produce.

Questions or ideas for a new tool? Get in touch.