Corrections Policy

Use the contact page and include as much of this as you can:

1. 1.The page, by its web address.
2. 2.What it says now, quoted or screenshotted.
3. 3.What you believe is correct, and why.
4. 4.For a calculator, the exact numbers you entered and the result you got. That is what lets us reproduce it.

You do not need to be certain, and you do not need to be an expert. "This number looks wrong to me" is a perfectly good report; working out whether it is wrong is our job.

We sort reports into three kinds:

• A calculation error. The formula or the code produces the wrong number. These are the most serious and get looked at first.
• A factual error. A size, standard, conversion or claim is wrong.
• An unclear explanation. The facts are right, but the wording misleads. We treat this as a real problem, not a quibble.

For factual claims we check against primary sources, chiefly the Craft Yarn Council standards. Where sources genuinely disagree, the fix is usually to say so on the page rather than to pick a side.

Calculator formulas live in plain, tested functions rather than being scattered through the page code. When we confirm an error, the fix is:

1. 1.Write a failing test that reproduces the wrong result.
2. 2.Correct the formula until the test passes.
3. 3.Run the full test suite so the fix does not break another tool.
4. 4.Update the published formula and worked example on the tool page, so the explanation still matches the code.

That test then stays in the suite permanently, which is what stops the same bug coming back.

• Minor fixes, such as a typo or clearer wording, are made quietly.
• Material corrections, where a number, instruction or fact was wrong, are noted on the page so you can see what changed and when.
• The "Last updated" date on an article changes when the content meaningfully changes.

We do not touch the updated date just to make old content look fresh. If the date moved, something actually changed.

• We will not quietly delete a page to make an error disappear.
• We will not dispute a well-evidenced correction to protect our own wording.
• We will not claim something was "always correct" after changing it.

If we got something wrong, the page will say what it now says, and the updated date will show when it changed.

You do not have to take our word for any calculation:

• Every tool page has a "The formula" section stating in plain words how the result is produced.
• Most tool pages include a worked example with real numbers you can follow by hand.
• Where a figure is an estimate rather than exact arithmetic, the page says so and lists what moves it.

If our stated formula and our stated example disagree with each other, that itself is a reportable error.