Frequently asked questions
- How accurate is this?
- The arithmetic is exact and uses decimal rather than floating-point maths, so results are not skewed by rounding. Where a calculation depends on legislation, the page shows which rule year it used, when those rules were last checked and the official source they came from. Results are estimates for information, not advice.
- Are my figures sent anywhere?
- No. Every calculation runs inside your browser. Nothing you type - salary, income, dates or amounts - is sent to our servers, stored or logged. You can disconnect from the network after the page loads and the calculator keeps working.