Hydraulic Hose Selection, Sizing and Installation
The right hose assembly is defined by seven pieces of information: inside diameter and length, temperature, application conditions, fluid, working…
EN 853 · EN 856 · ISO 1436 · SAE J517
Hydraulic Hose Dash Size Chart
Hydraulic hose dash sizes from -3 to -32, nominal inside diameter (inches and mm) and catalog DN equivalent; how hose size is measured and how it differs from tube dash sizes.
Quick answer
Hydraulic hose size is its nominal inside diameter, and the dash number gives this diameter in sixteenths of an inch. A -4 hose has a 1/4" (6.35 mm, DN6) ID, -6 is 3/8" (9.53 mm, DN10), -8 is 1/2" (12.7 mm, DN12), -12 is 3/4" (19.05 mm, DN19) and -16 is 1" (25.4 mm, DN25). On tube connections, the same dash number indicates the outside diameter.
EN 853 · EN 856 · ISO 1436 · SAE J517
Size chart
Hydraulic hose size conversion: dash, ID (inch, mm) and DN
| Dash size | Nominal IDin | Nominal ID (decimal)in | Nominal IDmm | DN (catalog notation) |
|---|---|---|---|---|
| -3 | 3/16 | 0.1875 | 4.76 | DN5 |
| -4 | 1/4 | 0.25 | 6.35 | DN6 |
| -5 | 5/16 | 0.3125 | 7.94 | DN8 |
| -6 | 3/8 | 0.375 | 9.53 | DN10 |
| -8 | 1/2 | 0.5 | 12.7 | DN12 |
| -10 | 5/8 | 0.625 | 15.88 | DN16 |
| -12 | 3/4 | 0.75 | 19.05 | DN19 |
| -16 | 1 | 1 | 25.4 | DN25 |
| -20 | 1-1/4 | 1.25 | 31.75 | DN31 |
| -24 | 1-1/2 | 1.5 | 38.1 | DN38 |
| -32 | 2 | 2 | 50.8 | DN51 |
Chart notes
- On hose, the dash size is the nominal ID in sixteenths of an inch: -8 hose = 1/2" = 12.7 mm ID. On tube (JIC, ORFS) the dash size is the OD, so the same dash means a different size on hose and tube.
- Hose DN indicates the approximate ID (mm) and should not be confused with pipe DN: 1/2" pipe = DN15, 1/2" hose ≈ DN12.
- Catalog DN notation may vary slightly between manufacturers (e.g. DN12 or DN13 for 1/2").
- This chart is for SAE 100R and EN type hydraulic hoses; on PTFE and motorsport hoses the actual ID may be smaller than nominal.
- mm values are calculated as inches × 25.4.
Reference standards
- EN 853
- Wire braid reinforced hydraulic hoses
- EN 856
- Spiral wire reinforced hydraulic hoses
- ISO 1436
- Wire braid reinforced hydraulic hoses
- SAE J517
- 100R series hydraulic hoses
Values are nominal; for critical applications, verify against the current standard and the manufacturer's catalog.
Description
Description
Hydraulic hose size is its nominal inside diameter. The dash number gives this diameter in sixteenths of an inch; in catalogs and on hose markings the same size is also written in inches, millimeters and DN. The chart lists the dash size, inches, millimeters and the common catalog DN equivalent together, from -3 to -32. Values are for SAE J517 (100R) and EN 853/856 type rubber hydraulic hoses.
How to read the chart
- Dash: -8 = 8/16" = 1/2" ID.
- ID (mm): calculated as inches × 25.4; some catalogs round the value (e.g. 6.3).
- DN: a catalog notation showing the approximate ID in millimeters: DN6, DN10, DN12, DN19, DN25. Some manufacturer codes may show different values, such as 13 for 1/2" or 32 for 1-1/4".
Dash sizes differ on hose and tube
On JIC and ORFS tube connections the dash number indicates the tube OD; on hose it indicates the ID: a -8 tube is 12.7 mm OD, while a -8 hose has a 12.7 mm ID. Hose DN also differs from pipe DN: 1/2" pipe is written as DN 15 and 1/2" hose as DN12. JIC ends with the same dash size are common on hose (a -8 hose with a -8 JIC end with a 3/4-16 UNF thread), but the end size can also differ from the hose size.
How to measure hose size
- Read the printing on the hose cover: it shows the standard (such as EN 853 2SN), the ID (dash, inch or DN) and the working pressure.
- If the printing is unreadable, measure the ID at a cut end. Don't go by the OD; the OD of hoses with the same ID varies with the reinforcement type.
- Measure the overall length from the sealing face of one end to the sealing face of the other.
- Note the connection type, thread and angle (straight, 45°, 90°) of both ends; if there are two angled ends, show the orientation between them in a photo.
Hose type and pressure
The ID determines the flow, while the hose type determines the pressure class. For EN 853 wire braided (1SN, 2SN) and EN 856 spiral reinforced (4SP, 4SH) hoses, the permitted working pressure is given by ID in the standard's table; on braided types the pressure drops as the diameter increases. This chart does not give pressure values. The pressure of a hose assembly is set by the lowest-rated part among the hose, fittings and adapters.
On stainless steel hose fittings
The ferrule and fitting must be chosen to suit the hose type; some types require the outer cover to be skived before crimping. The crimp diameter is set according to the hose and fitting manufacturer's table and checked by measurement after crimping. On AN/PTFE hoses the actual ID is smaller than nominal; this chart does not apply to them.
FAQ
Frequently asked questions
If your question isn't answered here, message us on WhatsApp with dimensions or a photo, and our technical team will answer directly.
What does the dash size mean on a hose?
On hose, the dash number gives the nominal inside diameter in sixteenths of an inch: -4 = 1/4" (6.35 mm), -8 = 1/2" (12.7 mm), -16 = 1" (25.4 mm). On tube connections (JIC, ORFS) the same number indicates the outside diameter; a -8 tube and a -8 hose are different physical sizes.
How many mm is a 1/2 hydraulic hose?
A 1/2" hydraulic hose has a nominal ID of 12.7 mm; its dash size is -8 and its catalog notation DN12. The OD varies with the hose type and is not used for sizing.
Is hose size measured by ID or OD?
By ID. Two hoses with the same ID can have different ODs depending on the reinforcement type (wire braid or spiral) and the number of layers. Read the printing on the hose first; if it is unreadable, measure the ID at a cut end.
What is the difference between 2SN and 4SH hose?
2SN is a hose defined in EN 853, reinforced with two layers of steel wire braid. 4SH, defined in EN 856, is reinforced with four spiral-wound steel wire layers and is used for higher pressure and pressure-shock service. The permitted working pressure of each type by ID is read from the standard and manufacturer's tables.
Is hose DN the same as pipe DN?
No. On hose, DN shows the approximate ID in millimeters (1/2" hose is DN12). On pipe, DN is the equivalent of the nominal pipe size (1/2" pipe is DN 15). When ordering, state whether the size refers to hose or pipe.
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