An improperly sized hose can cause excessive pressure drop, overheating, reduced flow, premature hose failure, or even catastrophic system damage.
This guide provides a complete hydraulic hose size chart covering all common sizes, dash numbers, inside diameters, outside diameters, pressure ratings, and typical applications.
Hydraulic Hose Size Chart
| Dash Size | ID (inches) | ID (mm) | OD (inches) | OD (mm) | Typical Working Pressure (PSI) | Burst Pressure (PSI) | Typical Applications |
|---|---|---|---|---|---|---|---|
| -2 | 0.125 | 3.2 | 0.28 | 7.1 | 6,000 | 24,000 | Instrumentation |
| -3 | 0.187 | 4.8 | 0.34 | 8.6 | 5,000 | 20,000 | Brake & pilot lines |
| -4 | 0.250 | 6.4 | 0.44 | 11.2 | 4,500 | 18,000 | Light hydraulics |
| -5 | 0.312 | 7.9 | 0.50 | 12.7 | 4,000 | 16,000 | Medium pressure |
| -6 | 0.375 | 9.5 | 0.56 | 14.2 | 4,000 | 16,000 | Mobile equipment |
| -8 | 0.500 | 12.7 | 0.72 | 18.3 | 3,000 | 12,000 | Industrial systems |
| -10 | 0.625 | 15.9 | 0.88 | 22.4 | 2,500 | 10,000 | Construction |
| -12 | 0.750 | 19.1 | 1.03 | 26.2 | 2,000 | 8,000 | Excavators |
| -14 | 0.875 | 22.2 | 1.15 | 29.2 | 1,800 | 7,200 | High-flow return |
| -16 | 1.000 | 25.4 | 1.28 | 32.5 | 1,500 | 6,000 | Loader hydraulics |
| -18 | 1.125 | 28.6 | 1.40 | 35.6 | 1,250 | 5,000 | Suction lines |
| -20 | 1.250 | 31.8 | 1.55 | 39.4 | 1,000 | 4,000 | Industrial presses |
| -24 | 1.500 | 38.1 | 1.90 | 48.3 | 800 | 3,200 | Oil transfer |
| -28 | 1.750 | 44.5 | 2.20 | 55.9 | 600 | 2,400 | Large machinery |
| -32 | 2.000 | 50.8 | 2.45 | 62.2 | 500 | 2,000 | Mining equipment |
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Hydraulic Hose Dash Size
| Dash Size | Fractional Size (inches) | Decimal ID (inches) | Metric ID (mm) |
|---|---|---|---|
| -2 | 1/8 | 0.125 | 3.2 |
| -3 | 3/16 | 0.187 | 4.8 |
| -4 | 1/4 | 0.250 | 6.4 |
| -5 | 5/16 | 0.312 | 7.9 |
| -6 | 3/8 | 0.375 | 9.5 |
| -8 | 1/2 | 0.500 | 12.7 |
| -10 | 5/8 | 0.625 | 15.9 |
| -12 | 3/4 | 0.750 | 19.1 |
| -14 | 7/8 | 0.875 | 22.2 |
| -16 | 1 | 1.000 | 25.4 |
| -18 | 1-1/8 | 1.125 | 28.6 |
| -20 | 1-1/4 | 1.250 | 31.8 |
| -24 | 1-1/2 | 1.500 | 38.1 |
| -28 | 1-3/4 | 1.750 | 44.5 |
| -32 | 2 | 2.000 | 50.8 |
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SAE Hydraulic Hose Pressure Ratings
| SAE Standard | Reinforcement Type | Min Working Pressure (PSI) | Max Working Pressure (PSI) | Typical Use |
|---|---|---|---|---|
| SAE 100R1AT | Single wire braid | 1,500 | 3,000 | General hydraulics |
| SAE 100R2AT | Double wire braid | 3,000 | 5,000 | High-pressure |
| SAE 100R3 | Textile braid | 300 | 900 | Low pressure |
| SAE 100R4 | Wire helix | Vacuum | 300 | Suction/return |
| SAE 100R5 | Textile cover | 1,000 | 3,000 | Automotive |
| SAE 100R6 | Textile braid | 300 | 1,000 | Return lines |
| SAE 100R12 | Four-wire spiral | 3,000 | 4,000 | Heavy duty |
| SAE 100R13 | Multi-spiral | 4,000 | 5,000 | Severe duty |
| SAE 100R15 | Multi-spiral | 4,000 | 6,000 | Extreme pressure |
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Hydraulic Hose Size vs Flow Rate
| Hose ID (inches) | Hose ID (mm) | Recommended Flow (GPM) | Velocity (ft/sec) | Application Type |
|---|---|---|---|---|
| 1/8 | 3.2 | 0.5–1 | High | Instrumentation |
| 3/16 | 4.8 | 1–2 | High | Control lines |
| 1/4 | 6.4 | 2–4 | Medium | Light systems |
| 5/16 | 7.9 | 4–6 | Medium | Auxiliary |
| 3/8 | 9.5 | 5–8 | Medium | Mobile hydraulics |
| 1/2 | 12.7 | 8–12 | Medium | Industrial |
| 5/8 | 15.9 | 12–18 | Low | Construction |
| 3/4 | 19.1 | 15–25 | Low | High-flow |
| 1 | 25.4 | 25–40 | Low | Main supply |
| 1-1/4 | 31.8 | 40–60 | Very Low | Return lines |
| 1-1/2 | 38.1 | 60–80 | Very Low | Oil transfer |
| 2 | 50.8 | 100–150 | Very Low | Bulk flow |
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Metric Hydraulic Hose Size
| Nominal Size (mm) | Inside Diameter (mm) | Inside Diameter (inches) | Equivalent Dash Size |
|---|---|---|---|
| 3 | 3.0 | 0.118 | -2 |
| 4 | 4.0 | 0.157 | -3 |
| 5 | 5.0 | 0.197 | -3 |
| 6 | 6.0 | 0.236 | -4 |
| 8 | 8.0 | 0.315 | -5 |
| 10 | 9.5 | 0.375 | -6 |
| 12 | 12.0 | 0.472 | -8 |
| 16 | 15.9 | 0.625 | -10 |
| 19 | 19.1 | 0.750 | -12 |
| 22 | 22.2 | 0.875 | -14 |
| 25 | 25.4 | 1.000 | -16 |
| 28 | 28.6 | 1.125 | -18 |
| 32 | 31.8 | 1.250 | -20 |
| 38 | 38.1 | 1.500 | -24 |
| 45 | 44.5 | 1.750 | -28 |
| 50 | 50.8 | 2.000 | -32 |
Understanding Hydraulic Hose Sizing
Hydraulic hoses are typically sized using a dash size system, which represents the hose’s inside diameter (ID) in sixteenths of an inch.
- Dash size: Indicates hose ID
- Inside Diameter (ID): Controls flow rate
- Outside Diameter (OD): Important for routing and clamp clearance
- Working Pressure: Maximum safe operating pressure
- Burst Pressure: Usually four times the working pressure
Correct sizing ensures optimal fluid velocity, minimal pressure loss, and long hose life.
How to Choose the Correct Hydraulic Hose Size
- Determine flow rate (GPM) required by the system
- Check working pressure and pressure spikes
- Select proper ID to maintain safe fluid velocity
- Verify OD clearance for routing and fittings
- Match hose type to temperature and fluid compatibility
Never undersize a hose to save space; pressure loss and heat damage will follow.
Common Hydraulic Hose Sizing Mistakes
- Using the outside diameter instead of the inside diameter
- Ignoring pressure spikes
- Mixing metric and SAE sizes
- Choosing hose size based on fittings alone
- Oversizing suction lines without checking the bend radius
Final Thoughts
A reliable hydraulic system starts with the right hose size. This hydraulic hose size chart provides a comprehensive reference for dash sizes, diameters, pressure ratings, and applications across all common hydraulic systems. Always confirm manufacturer specifications and SAE standards before final installation, especially in high-pressure environments.
