About ToolboxDay
ToolboxDay is a collection of free calculators and everyday tools. This page explains who runs it, how the tools are made and checked, and how you can hold us to account.
Who runs ToolboxDay
ToolboxDay is operated by SaracAI, a sole proprietorship in Frankfurt am Main, Germany. We are not a corporation or a large editorial team, but a small business that builds and maintains its own tools.
Full provider details are in the legal notice (Impressum).
How we work
ToolboxDay is made by SaracAI: we build, check and maintain every tool ourselves. The person responsible for the content under German media law is named in the legal notice.
The same rules apply to every tool: every calculation rule needs a source, and that source is shown on the page. Calculations run in your browser, with no sign-up and without your input ever reaching us. And every calculation is checked: by automated tests before publication and by fact checks against the source afterwards.
Questions, suggestions and error reports reach us through the contact page.
Our mission
Tools that are fast and work without detours: free, with no account, no sign-up and no file upload. Calculations run in your browser, and the pages work equally well on phones and computers.
The site is funded by advertising. Ads have no influence on results or sources.
How tools are made and checked
Every tool starts with a question many people really have. Where possible we take rules, formulas, deadlines and values from primary sources: laws and regulations, official publications, standards and specialist literature. The sources are listed on each tool page.
Automated tests protect the calculation logic by checking known examples and edge cases against the source. In addition, browser tests open the pages in all 11 languages so that input, result and text work in each language.
If a figure depends on the version of a law or a table, we give the date we last checked it.
Every figure needs a source
No value without evidence: every tool page lists under “Sources” what the calculation is based on, together with the date it was last checked. The order of sources is fixed: official sources such as laws, regulations and publications of authorities and standards bodies come first, followed by specialist sources such as professional societies and recognised textbooks. News and advice sites are used only for context, never as the sole evidence.
Many rules apply in one country only, such as taxes, deadlines or public holidays. Tools of this kind rely on the sources of that country and name them on the page.
Fact checks after publication
In addition to the automated tests, published tools are recalculated in separate review rounds: formula, limits and examples are compared with the source once more, independently of the original implementation.
If such a fact check finds an error, the page is corrected and the case is recorded as an automated test, so the same error cannot quietly return.
Guidance, not advice
Health, tax and finance calculators show how a value is calculated according to the cited source. They do not replace legal, tax, financial or medical advice. For binding decisions, the official source or the advice of a licensed professional applies.
Our privacy principle
What you type into our calculators is not sent to us: it stays in your browser. There is no account and no form. A few tools have to fetch a third-party web address, for example website checks; they say so explicitly on the page.
Details, including advertising and consent, are in the privacy policy.
Reporting an error
Mistakes happen. If a result looks wrong or a text is unclear, please send us the address of the page and the values you entered. We check the report against the source and correct the page if it was wrong.