Watering and hoses
How to measure garden hose diameter
Hose size always refers to the inside diameter, not the outside of the hose and not the fitting. You can measure it in under a minute.
Updated 26 Oct 2026 · Facts checked against the sources at the end.
Step by step
- Check the label first. Many hoses have the size printed along the side or on the coupling.
- Find an open end. Unscrew the hose from the faucet so you can see into the end, or look at a cut end if you are repairing it.
- Measure across the inside. Hold a ruler or tape across the opening and measure from inner wall to inner wall.
- Match to the nearest size. About 1/2 inch, 5/8 inch or 3/4 inch.
It is easiest to measure a cut end of hose. Inside a coupling, the opening may be narrower than the hose itself.
Inches to millimeters
| Inside diameter | Approximate mm |
|---|---|
| 1/2 inch | 12.7 mm |
| 5/8 inch | 15.9 mm |
| 3/4 inch | 19.1 mm |
Why the fitting size is different
The fittings on a US garden hose are usually 3/4 inch garden hose thread no matter what the hose diameter is. So a 5/8 inch hose still screws onto a standard faucet. See garden hose thread size.
When you need the exact size
- Buying a repair coupling or mender: it must match the hose's inside diameter.
- Choosing a hose reel: capacity is listed by length for a given diameter.
- Comparing flow: a wider hose carries more water. See garden hose flow rate.
Frequently asked questions
Is hose size measured inside or outside?
Inside. Garden hose size is the inside diameter of the hose.
How can I tell if my hose is 1/2 or 5/8?
Check the printed label, or measure across the inside of a cut end: about 0.5 inch means 1/2 inch, about 0.63 inch means 5/8 inch.
Do I need the hose diameter to buy a repair kit?
Yes. Hose menders and replacement ends are sized by the hose's inside diameter.
Related
Sources
Written in our own words from the sources above. See our editorial policy. Spotted a mistake? Tell us.