Report an Error
Found a wrong number? This page exists because I would rather fix it than defend it.
What helps most
Every figure on this site traces back to a published source, and every report is checked against that source by me personally. Three details make the check fast.
The page address. The exact page where the problem is, copied from your address bar. A pace that is wrong on the chart but right in the converter is a different bug from a formula that is wrong everywhere, and the address tells me which one I am looking for.
The numbers you entered. What you put into the calculator — the speed, pace, incline, distance or age, with its units — and the result it gave you, exactly as it appeared. Most apparent errors turn out to be a units mix-up, miles read as kilometres or the other way round, which is exactly why the units help.
What you expected, and what you saw. The result you believe is right, set against the one the page showed — and, if you have it, where your figure comes from: a published table, a study, or your own hand calculation from the formula on the Methodology page. If the wrong number came from a worked example in the text rather than the calculator itself, say so — examples and live code are checked separately.
Send the report
The button below opens your own mail app with the report addressed and the subject filled in — this site has no server to send it to, and nothing leaves your device until you press send in that app. Add the three details above, in any order, and send it.
Prefer to write it yourself? Email the same details to ianwelkins@gmail.com.
What happens next
Your report is checked against the source formula named on the page — not against my memory of what the answer should be. If the site is right and the difference is a units setting or an estimate doing what estimates do, I will write back and show the working. If the report is a real error, it is fixed in the underlying code or data, every worked example on the affected pages is re-run through the test harness, and the correction is fixed and logged with a date, as the editorial policy describes. Either way, you hear back.
Thank you for reporting it. A calculator site is only as trustworthy as its corrections, and most of the fixes that matter start with a reader who bothered to check.