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.

Who runs the site

CalcOak is an independent, self-funded project run by a small team with a background in e-commerce operations and web development. We are not affiliated with any carrier, tax authority, bank or software vendor mentioned on the site; company and product names appear only to identify the rules being described. Every tool and guide is written and checked by us, and each page shows when it was last updated where that matters.

How we decide what to build

A tool earns a place here when three things are true: the question comes up often, the honest answer needs more than a single multiplication, and the existing calculators we could find skip the detail that changes the result. Our guides exist for the same reason. They explain the rule behind each tool, with worked examples, so you can check a figure by hand and know when the simple formula does not apply.

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, and the rules for using the site are in our terms of use.

Get in touch

Corrections, requests for a new tool and questions are all welcome through thecontact page or by email at hello@calcoak.com. We read everything and reply to anything that needs an answer.