Report an Issue

What to include in a report

A good report lets us reproduce the problem in a minute or two. Please tell us which calculator or page, the exact numbers you entered, the result you saw and the result you expected. If you have a source for the expected number, such as a service manual, a manufacturer's chart or a hand calculation, mention it. Say which device and browser you were using if the page looked or behaved oddly.

Before you report a wrong answer

• Check units. Mixing inches and millimeters, or pounds per hour and cc per minute, is the most common reason for an unexpected result.
• Check which figure the tool expects. Crank horsepower and wheel horsepower, static and dynamic compression, rim width and overall wheel width all look similar but give very different answers.
• Read the formula section on the page. Every calculator shows its formula and the assumptions behind it, and our How We Calculate page explains our approach.
• Try the guide. Many results make more sense after reading the matching guide.

What happens after you send it

Reports about wrong numbers come first. We check the formula and the source, fix the page if there is an error, and note the correction. Reports about layout or a bug in the page are checked on the devices we can test. We can't diagnose a vehicle or tell you whether a job is safe, but we can tell you whether the tool is doing what it says it does.