Hydraulic Hose Size Chart
Hydraulic hose is sized by inside diameter, and the dash number is simply that diameter counted in sixteenths of an inch. A -08 hose is eight sixteenths, or 1/2 inch. Once you know that, the rest of the sizing system falls into place.
Dash size to inside diameter
| Dash size | Nominal ID (in) | Nominal ID (mm) |
|---|---|---|
| -04 | 1/4″ | 6.4 |
| -05 | 5/16″ | 7.9 |
| -06 | 3/8″ | 9.5 |
| -08 | 1/2″ | 12.7 |
| -10 | 5/8″ | 15.9 |
| -12 | 3/4″ | 19.0 |
| -16 | 1″ | 25.4 |
| -20 | 1-1/4″ | 31.8 |
| -24 | 1-1/2″ | 38.1 |
| -32 | 2″ | 50.8 |
The one exception worth remembering is -05, which is 5/16 inch rather than a neat fraction, and the larger spiral sizes where the dash number stops tracking sixteenths exactly. Always confirm against the layline printed on the hose.
Careful: hose dash and fitting dash are not always the same
A hose end is described by two numbers — the hose it crimps onto and the thread on the other end. A fitting written as 3/8″ hose x -8 JIC means a -06 hose with a -08 thread. Stepping up or down a thread size on a given hose is normal and often exactly what the job needs. When you order, give us both numbers.
Which hose type do I need?
| Hose type | Construction | Typical use |
|---|---|---|
| SAE 100R1AT | One wire braid | General purpose medium pressure lines |
| SAE 100R2AT | Two wire braid | General purpose higher pressure lines |
| SAE 100R16 | Two wire braid, compact | Same duty as R2AT where routing is tight — smaller OD and tighter bend radius |
| SAE 100R17 | Wire braid, constant pressure | One pressure rating across the size range, simplifies design and stocking |
| SAE 100R12 | Four wire spiral | High pressure, high impulse duty on heavy equipment |
| DIN 4SP | Four wire spiral | High pressure metric equivalent to R12 duty |
| DIN 4SH | Multi-wire spiral | The highest pressure spiral construction we stock |
| SAE 100R7 | Thermoplastic, one braid | Lightweight, tight bend radius, lift and aerial equipment |
| SAE 100R8 | Thermoplastic, higher rating | Same benefits as R7 at a higher pressure rating |
| SAE 100R3 | Textile braid | Low pressure return and drain lines |
| SAE 100R4 | Textile braid with helix wire | Suction and low pressure return, resists collapse |
| SAE 100R6 | Single textile braid | Low pressure lines and lubrication |
Working pressure changes with size within every one of these families, and it always falls as diameter rises. Never pick a hose on construction alone — check the rating for the specific size you are buying, and keep the system’s peak pressure, not its average, in mind.
Measuring a hose you need to replace
- Read the layline first. Most hose is printed with its type and size along the cover. If it is legible, you are done.
- If it is worn off, measure the inside diameter at a clean cut end and convert with the table above.
- Count the reinforcement layers at the cut. One braid, two braids and four spiral layers look clearly different in cross section, and they tell you the pressure class.
- Measure length seat to seat. For hose assemblies, the convention is the overall length between the sealing faces of the two end fittings, not the length of the rubber. Getting this wrong by an inch is the most common remake we see.
- Note the fitting orientation. On an assembly with two elbows, the angle between them matters. Mark it before you cut the old one off.
Bend radius
Every hose has a minimum bend radius, and going tighter than it is one of the fastest ways to shorten hose life — the reinforcement gets pulled apart on the outside of the bend and buckles on the inside. If a route is tight, move to a compact construction such as R16 or R17, use an elbow fitting to start the bend at the port, or step to thermoplastic. Never let a bend start right at the fitting; leave a straight section at least twice the hose diameter before the curve.
One piece and two piece hose ends
A one piece fitting is a single component that crimps directly onto the hose. It is quick, has fewer parts to stock, and is the usual choice for braided hose in a busy shop.
A two piece fitting is a stem plus a separate ferrule. It costs a little more in handling but lets you mix and match, and it is what the spiral and interlock constructions use. Our two piece stems come in three families:
| Stem series | Type |
|---|---|
| 23 Series | Two piece crimp stem, braided hose |
| 24 Series | Two piece crimp stem, spiral hose |
| 26 Series | Two piece interlock stem, spiral hose |
Matching a ferrule to your hose
The ferrule is not generic. It is cut for a specific reinforcement type, and using the wrong series will either fail to grip or cut into the wire. This is the mapping we stock to:
| Ferrule series | Designed for |
|---|---|
| 20-101 | One wire hose |
| 20-107 | Thermoplastic hose |
| 20-201 | Textile braid and two wire hose |
| 20-202 | One and two wire and textile braid hose |
| 20-204 | One and two wire hose |
| 20-301 | One wire hose |
| 20-302 | One and two wire hose |
| 20-305 | R17 compact hose |
| 20-400 | Four wire spiral hose (skive) |
| 20-405 | Four wire spiral hose (interlock) |
| 20-406 | Four and six wire spiral hose (interlock) |
| 20-NS4 | Four wire spiral hose (non-skive) |
| 20-TFC | Corrugated PTFE hose |
Skive and non-skive matters too. A skive ferrule expects the cover to be stripped back to the wire before crimping; a non-skive ferrule bites through the cover. Do not swap one for the other.
Let us build it
If you would rather not work out the combination yourself, use our build a hose tool — pick the hose, both ends and the length and we will crimp and test it. You can also shop hose ends and hose fittings directly, or identify the thread on your port first with the thread identification chart. The rest of our reference charts are here.