How we build and check our calculators

1. The formula is always visible

Each calculator page has a “The formula” section that writes out every step in plain language. If a result surprises you, you can follow the working yourself.

2. Worked examples are tested automatically

Every worked example on the site is also an automated test. Before any change is published, our test suite runs each example through the same engine that powers the calculator and fails if the answer differs from the one in the text.

3. Default values come from published sources

For pricing calculators, defaults are typical figures from published cost guides, which we link under “Sources for the default values”. Prices vary a lot by region, so treat defaults as a starting point and enter your own numbers.

4. Rules that change get dated

Where a result depends on a rule that changes, such as India's GST slabs or US solar incentives, the page says which rule it uses and when the page was last updated.

5. Estimates, not advice

Results are estimates for planning. They are not financial, tax, legal or engineering advice. For decisions with real money at stake, confirm with a qualified professional.

Corrections

If you find an error, email hello@calculatordash.com. We fix confirmed mistakes promptly and update the page date.