About CalcFree
Last updated 2 June 2026.
CalcFree is a small, independent site of calculators for tax, money and real-world projects. It exists for one reason: most online calculators don’t show their working. They give you a number with no sense of what it assumed, what rules it used, or whether those rules are still current. When you’re trying to make a decision — claim a refund, weigh up a contract, budget a project — that’s not good enough.
Why CalcFree exists
Every tool here is built to be understood, not just used. Alongside each calculator you’ll find the assumptions written in plain English, a link to the official source, and an honest note about what the tool can’t do. The point isn’t to replace professional advice; it’s to help you understand the number well enough to know when you need that advice.
How the calculations work
The calculation logic is written in code so it can be tested with worked examples, while the figures it relies on — tax bands, thresholds, typical prices — live in separate, editable data files. That separation matters: it means a rate can be updated for a new tax year without touching the maths, and the maths can be checked independently of the rates. Calculations run in your browser, so the numbers you type aren’t sent anywhere or stored.
Limitations
A calculator is a model, and every model simplifies. Our tools cover the common cases well and say so when they don’t handle something — other income, unusual tax codes, regional variations, and anything genuinely complex like inheritance tax or IR35 edge cases. Treat every result as a planning estimate, not a final figure or financial, tax or legal advice.
How figures are kept up to date
Rates and prices are reviewed each tax year, or sooner when rules change, and every tool carries a visible “last reviewed” date. Our Methodology, Sources and Editorial pages explain in more detail how tools are built, how data is chosen, and how errors are corrected. If you spot something that looks wrong, the Contact page tells you how to flag it.
CalcFree is built and maintained by Techithrive, a web development studio. The site is free to use and supported by advertising.
Built by Techithrive
CalcFree is an independent digital publishing platform. The technology behind it — the calculator framework, content system and performance work — is engineered by Techithrive, a studio that builds calculator platforms, web applications, content systems and performance-focused websites. CalcFree is run as its own publishing project; Techithrive’s role is the engineering underneath it. You can read more about how CalcFree is built.