Rubber hoses are one of the most widely used hose types worldwide. They make up roughly 38% of the global hose market. The reason is, these hoses are used in automotive, agriculture, construction, manufacturing and many other industries.
With so many applications, rubber hose sizes also vary widely. Today, we will cover the rubber hose size chart, dash size, wall thickness, working pressure and SAE specifications for rubber hose.
Standard Rubber Hose Sizes
Rubber hoses are available in a wide range of sizes to meet different application needs. The most common specification depends on the hose’s inside diameter (ID), outside diameter (OD) and wall thickness.
ID is the internal diameter of the hose bore and OD is the external diameter measured across the rubber hose’s outer surface. Wall thickness is the distance between the hose’s inner surface and outer surface. It basically indicates how thick the rubber layer is around the hose bore.
| ID (inch) | ID (mm) | OD (mm) | Wall Thickness | Application |
| 1/8″ | 3.2 mm | 7 to 8 mm | 1.9-2.4 mm | Small-scale/low-flow fluid, air or vacuum lines |
| 3/16″ | 4.8 mm | 9 to 10 mm | 2.0-2.6 mm | Oil cooler/ crankcase breather hoses & pneumatic air lines |
| 1/4″ | 6.3 mm | 11-13 mm | 2.6 to 3.35 mm | Low pressure fluid & oil transfer and compressed air lines |
| 5/16″ | 7.9 mm | 14 to 15 mm | 2.8 to 3.55 mm | Engine fuel, low pressure hydraulic & return lines |
| 3/8″ | 9.5 mm | 16-18 mm | 3.0-4.0 mm | Pneumatic air hoses, high temperature water/coolant lines |
| 1/2″ | 12.7 mm | 20 to 22 mm | 3.4 to 4.65 mm | Coolant/heater hose and heavy-duty fluid transfer |
| 5/8″ | 15.9 mm | 23-25 mm | 3.55-4.8 mm | Automotive heater hoses and high-flow garden hoses |
| 3/4″ | 19.0 mm | 27 to 30 mm | 4.0 to 5.25 mm | Industrial water/air lines and radiator hose |
| 1″ | 25.4 mm | 34-37 mm | 4.3 to 5.8 mm | Radiator main coolant lines plus fluid suction/discharge |
| 1-1/4″ | 31.8 mm | 42 to 45 mm | 4.85-6.6 mm | Engine cooling and heavy industrial water discharge |
| 1-1/2″ | 38.1 mm | 48-52 mm | 4.95 to 6.95 mm | Marine wet exhaust & bulk liquid transfer |
| 2″ | 50.8 mm | 62-66 mm | 5.6 to 7.6 mm | Heavy suction/discharge and agricultural pumping |
Rubber Hose Working Pressure vs Burst Pressure
The working pressure is maximum pressure a rubber hose can safely handle during normal operation. You should keep system pressure at or below this rating. On the other hand, burst pressure is the pressure at which the hose can fail or burst. It does not represent a safe operating limit.
Rubber hose standards commonly use a 3:1 or 4:1 safety factor. It means, the burst pressure can be three to four times higher than the working pressure. Some high-pressure static applications use a 2:1 safety factor. In this case, the burst pressure can be twice the working pressure.
| Rubber Hose Category | Working Pressure Range (WP) | Burst Pressure Range (3:1 to 4:1 Ratio) |
| Low pressure hoses | 100 to 300 psi (7 to 20 bar) | 300 to 1200 psi (21 to 83 bar) |
| Medium pressure hoses | 300 to 3000 psi (20 to 207 bar) | 1200 to 12000 psi (83 to 827 bar) |
| High-pressure hoses | 3000 to 10000+ PSI (207 to 690+ bar) | 12000 to 40000+ psi (827 to 2758+ bar) |
How Reinforcement Affects Rubber Hose OD?
Reinforcement definitely adds extra layers or materials around the hose bore. This will increase the overall outside diameter of tube. A hose with one reinforcement layer has a smaller OD than a hose with multiple layers even when both have the same inside diameter (ID). In fact, the number/type of layers also decide the hose’s pressure capacity.
| Hose Construction | Related SAE Type | Pressure Level | Expected Change in OD |
| 1 wire braid | SAE 100R | Medium pressure | Adds some thickness |
| 2 wire braid | SAE 100R2 | High pressure | Creates a thicker hose wall |
| 3 wire braid | SAE 100R12/R15 | Very high pressure | Produces a noticeably larger hose diameter |
Note: For reinforced rubber hydraulic hoses, SAE J517 provides standards for hose constructions. Common types include SAE 100R1, 100R2, 100R12 and 100R15. These specifications define requirements such as reinforcement and pressure performance. So you can select the right rubber hose for a hydraulic system.
Rubber Hose Dash Size Chart
What is dash size? Rubber hose manufacturers and suppliers use dash sizes to identify hose specification quickly. Dash size is a numerical code used to identify a hose’s nominal inside diameter in sixteenths of an inch. It is commonly written with a dash (-) before the number. Each dash number relates to the hose’s approximate inside diameter.
| Dash Size | Nominal ID (mm) | Nominal Hose ID (inch) |
| -2 | 3.2 mm | ⅛ inch |
| -3 | 4.8 mm | 3/16 inch |
| -4 | 6.4 mm | ¼ inch |
| -5 | 7.9 mm | 5/16 inch |
| -6 | 9.5 mm | ⅜ inch |
| -8 | 12.7 mm | ½ inch |
| -10 | 15.9 mm | ⅝ inch |
| -12 | 19.1 mm | ¾ inch |
| -16 | 25.4 mm | 1 inch |
| -20 | 31.8 mm | 1¼ inch |
| -24 | 38.1 mm | 1½ inch |
| -32 | 50.8 mm | 2 inches |
Rubber Hose Length Tolerances Under ISO 1307
ISO 1307 specifies the acceptable length tolerance for cut-to-length rubber hoses. This means the actual hose length can be slightly shorter or longer than the ordered length.
| Ordered Length | Permitted Length Variation |
| Above 1800 mm | ±1% of the specified length |
| 1201 to 1800 mm | ±12 mm |
| 901 to 1200 mm | ±9 mm |
| 601 – 900 mm | ±6 mm |
| 301 – 600 mm | ±4.5 mm |
| Up to 300 mm | ±3 mm |
How To Measure Rubber Hose?
Check your measuring tool: The first thing you need is a tape measure and check the smallest measurement on it. For example, if there are 16 small spaces between 12 and 13 inches, then each mark equals 1/16 inch.
Measure inside diameter (ID): Now place the tape measure across the inside opening of the hose and get the dimensions from one inner edge to the other.
Convert measurement: For example, if the opening measures 6/16 inch, you can simplify it to 3/8 inch. So, the hose has a 3/8-inch inside diameter.
Measure hose length: To assess the length of a rubber hose, you need to put the tape measure at one end of the hose. Then you should follow the hose along its curve or bends until you reach the other end. Do not pull the hose straight or stretch. This will give you the actual length of the hose.
Choose right replacement size: The final step is to match the measured ID with the nearest standard hose size. For length, choose a slightly longer hose if the application requires extra room for installation.
Frequently Asked Questions
Does a 1-inch Rubber Hose Have a 1-inch OD?
No, a 1-inch rubber hose generally refers to a nominal inside diameter (ID) of 1 inch (25.4 mm), not its outside diameter. The actual OD depends on the hose’s wall thickness and construction. So a 1-inch hose will normally have an OD greater than 1 inch.
What’s Bigger: 5 /16 or 3/8 inch Rubber Hose?
A 3/8-inch rubber hose is larger than a 5/16-inch rubber hose because it has a wider inside diameter. It means, 3/8 hose can allow more fluid or air to pass through than 5/16 hose if conditions are the same.
Where Can I Buy Rubber Hose?
RONTEIX is your trusted business partner if you want to order rubber hoses in small quantities or bulk. You will get hose in a wide range of inner diameters for air, water or other fluid applications. Size ranges include 1/4″, 3/8″, 1/2″, 3/4″, 1-1/2″ and 2″ with custom sizes available to meet your specific requirements.
Final Note
Hose size and diameter selection is not something you should guess. It requires good understanding about the measurements and industry needs. We recommend you to also check the manufacturer’s specifications and applicable hose sizing standards before you make a final purchase.
RONTEIX offers a variety of rubber hoses in standard as well as customized sizes. You can contact our team or download the RONTEIX’s catalog to find rubber hoses in different sizes and shapes.
