Inch to cm/mm converter makes unit conversions quick and reliable for plumbing and water filter servicing. It is especially useful for RO tubing, quick-connect fittings and connectors where sizes are often specified in inches only.
By converting inches to cm and mm you can compare parts, match tubing diameters and avoid ordering mistakes. Keep in mind that inch labels in plumbing are often nominal, so measuring with a caliper is recommended.
FAQ - Inch to cm/mm converter
How many mm is 1/4 inch?
1/4" equals 6.35 mm. In RO systems, 1/4" is a very common tubing size.
How do I convert inches to mm?
Multiply inches by 25.4. This is the standard conversion for linear dimensions.
What is the difference between inch and DN?
Inch is a length unit, while DN is a nominal size used for pipes/valves. DN is not a direct inch-to-mm conversion.
Why does 1/2" not always mean 12.7 mm pipe diameter?
In plumbing, 1/2" is often a nominal thread/pipe designation. Actual inside/outside diameters can differ.
How should I read tubing and hose markings?
Sizes may be given in inches (e.g., 1/4") or mm. Check whether the value refers to outside or inside diameter.
What are common RO sizes?
Most RO tubing is 1/4" or 3/8". Threaded connectors often use 1/4" and 3/8" as well.
Should I verify the size with measurements?
Yes, especially when mixing brands. A simple caliper check helps avoid leaks and returns.