Nominal 3/8 inch inside diameter.
Hose Dash Size Converter
Convert AN, JIC, and hydraulic hose dash sizes to nominal inside diameter in inches and millimeters. Enter a dash size like -6, choose a common preset, or enter an inside diameter to find the closest dash size.
Convert a hose dash size
Dash sizes are usually based on sixteenths of an inch. Results update instantly.
A -6 hose is 6/16 inch, which simplifies to 3/8 inch or 9.53 mm nominal inside diameter.
How hose dash sizes work
For common AN, JIC, and hydraulic hose sizing, the dash number points to nominal hose inside diameter in sixteenths of an inch. A -4 hose is 4/16 inch, or 1/4 inch. A -8 hose is 8/16 inch, or 1/2 inch.
The dash number is a fast sizing shorthand. Always confirm the exact hose series, fitting style, pressure rating, temperature range, and manufacturer chart before buying parts for a critical system.
Common examples
- -3 hose ≈ 3/16 in ID ≈ 4.76 mm
- -4 hose ≈ 1/4 in ID ≈ 6.35 mm
- -6 hose ≈ 3/8 in ID ≈ 9.53 mm
- -8 hose ≈ 1/2 in ID ≈ 12.70 mm
- -12 hose ≈ 3/4 in ID ≈ 19.05 mm
Hose dash size chart
| Dash size | Fractional ID | Decimal inches | Millimeters | Typical note |
|---|
Hose dash size FAQ
What size is -4 hose?
A -4 hose is nominally 4/16 inch inside diameter, which simplifies to 1/4 inch or 6.35 mm.
What size is -8 hose in inches?
A -8 hose is nominally 8/16 inch inside diameter, which simplifies to 1/2 inch or 12.70 mm.
Does dash size tell me the fitting thread size?
Not by itself. Dash size is commonly used for hose or tube size, while the fitting thread standard is a separate detail. Check the fitting type, thread, flare, seat, and manufacturer specifications.