About CalcOak

CalcOak started as a handful of calculators we kept rebuilding in spreadsheets: how much a parcel would be billed at, whether the big bag of rice was actually cheaper, which Tuesday was ten working days away. Putting them on a single site meant we could stop hunting for them, and it seemed a waste not to share.

How the tools are built

Every tool on this site is plain HTML and JavaScript that runs entirely in your browser. When you type a number into a form, the result is calculated on your device and never sent to a server. That keeps the pages fast, keeps your data private, and means the tools keep working even if our hosting has a bad day and you have the page open already.

We try to make each tool genuinely useful rather than a thin wrapper around a formula. That usually means adding the details that generic calculators leave out: the actual divisors carriers use for dimensional weight, the public holidays of a specific country, the reduced VAT rate as well as the standard one. If a tool is missing a detail you rely on, tell us and we will look at adding it.

Accuracy

We check the tools against published reference values and real-world examples, but tax rates change, carriers revise their rules, and governments move holidays. Treat the output as a fast, well-informed estimate and confirm anything that matters financially or legally against the official source. If you spot a wrong figure, please get in touch; corrections are usually live within a day or two.

How the site is funded

CalcOak is free to use and is supported by advertising. We show a small number of ads served by Google AdSense, kept away from the tool itself so they never get in the way of the result. Details of what that involves for cookies and personalised ads are in our privacy policy.