Who makes it
avgcalc.com is built and run by David Choi, an independent founder based in Las Vegas, Nevada. David also builds pitchchanger.io, a set of free browser audio tools, and voltdrop.app, a voltage-drop calculator for electricians. avgcalc grew out of the same idea: a calculator should give the answer, show the working, and not ask for anything in return.
How the maths is checked
The calculation code is covered by automated tests that run before every release. Representative pages are checked in desktop and phone browsers before major releases, including the numbers they produce. Important changes also receive a separate code review from a second reviewer before they go live. The exact rules every calculator follows are written out on the methods page. Where a calculator uses an approximation (for example 30.44 days in a month, or sample rather than population standard deviation), the page says so next to the result.
What is not collected
The numbers you type are processed by JavaScript in your own browser and are never sent to a server. There are no accounts, uploads or sign-ups. The only third-party script is Google Analytics 4, which runs on the live site only, so we can see which calculators people use. The privacy policy has the full list.
Found a wrong answer?
Email hello@avgcalc.com with the page, the numbers you entered and the answer you expected. Corrections ship quickly, and every page carries the date it was last updated.
Citing avgcalc
You are welcome to link to or cite any page. A short form is: "avgcalc.com, page title, updated date shown on the page." Machine-readable summaries of the site are at /llms.txt and /llms-full.txt.