Frequently asked questions
How the tools work, where to check the method, and what the results can and cannot tell you.
Good to know before you calculate
01Are Calculation Guide calculators free to use?
Yes. The calculators currently published on this site can be used without an account or payment.
02Where can I see the formula for a result?
Each calculator page has a Formula panel, full equations or counting rules, definitions of every term, and a worked example. The result panel also describes the steps used for your own inputs.
03Are my entries sent to a server?
No. Calculation inputs are processed in your browser. The current application does not send them to a calculation server or save them in an account.
04Why might a result differ from another calculator?
Tools can use different rounding, date conventions, units or assumptions. Check the method and limitations shown on the relevant Calculation Guide tool page before comparing results.
05Can I use financial or health results as professional advice?
No. These tools explain calculations and estimates. They do not account for every contract term or personal medical factor; use a qualified professional and official records for decisions that depend on them.
06Why do some tools ask me to enter a rate or price?
Exchange rates, gold prices and electricity tariffs change often and differ by provider. Using the figure from your own bank, jeweller or bill keeps the result accurate and avoids a stored rate going stale.
07Do ads affect the results?
No. Ads, when shown, are labeled and separate from the calculator. They do not change a formula, a result or the wording of any page.
08How do I report an error or suggest a tool?
Use the Contact page to send a correction or idea. Include the tool name and a simplified example, and avoid sensitive personal details. Each tool lists its assumptions so you can describe a discrepancy precisely.
Need more detail? See the calculation methodology, read a worked example in the articles, or choose a tool from the calculator directory.