Tool · Nozzle tips and turbo nozzles
Nozzle size finder
Pick a nozzle size to see its orifice, its flow at common pressures and the tips made in it, and work out your machine's size from its rated PSI and GPM.
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Short answer
Pick a nozzle size to see its orifice diameter, its flow at common pressures and the tips, turbo nozzles and cannon orifices made in that size. To find your machine's size, put its rated PSI and GPM into the formula Cat Pumps and General Pump publish, worked through below.
Picks this tool points toSee the shortlist
- Nozzle size 2.5
- Nozzle size 3.0
- Nozzle size 3.5
- Nozzle size 4.0
Choose your nozzle size to see the key facts and what fits. Each fact links to its source on the full page.
All nozzle orifice sizes
What the table shows
| Nozzle size | Orifice diameter | Flow at common pressures | Parts made in this size |
|---|---|---|---|
| Nozzle size 2.5 | 0.039 in (General Pump chart equivalent orifice diameter) | 2.17 GPM at 3,000 PSI (General Pump chart). Calculated with the formula Cat Pumps and General Pump publish: about 1.53 GPM at 1,500 PSI, 1.77 GPM at 2,000 PSI and 2.5 GPM at 4,000 PSI | Not confirmed |
| Nozzle size 3.0 | Cat Pumps gives 0.043 in for a size 3.0 nozzle. MTM Hydro labels the 1.1 mm orifice in its PF22.2 foam cannon kit as size 3.0 | 3.0 GPM at 4,000 PSI (Cat Pumps). Calculated with the formula Cat Pumps and General Pump publish: about 1.84 GPM at 1,500 PSI, 2.12 at 2,000 PSI, 2.60 at 3,000 PSI and 2.77 at 3,400 PSI | DEWALT DXPA34ST five-tip set (0, 15, 25, 40 degrees and soap) and DXPA34TN turbo nozzle, both 1/4 in quick-connect and rated to 3,400 PSI; MTM Hydro's 1.1 mm foam cannon orifice in the PF22.2 kit |
| Nozzle size 3.5 | MTM Hydro labels the 1.25 mm orifice installed in its PF22.2 foam cannon as size 3.5 | Calculated with the formula Cat Pumps and General Pump publish: about 2.14 GPM at 1,500 PSI, 2.47 at 2,000 PSI, 3.03 at 3,000 PSI and 3.5 at 4,000 PSI | MTM Hydro's 1.25 mm orifice, installed in the PF22.2 foam cannon (SKU 14.5013) |
| Nozzle size 4.0 | 0.052 in (General Pump chart; Cat Pumps gives the same for a 4-25 nozzle) | 4.00 GPM at 4,000 PSI, about 3.46 GPM at 3,000 PSI and about 2.83 GPM at 2,000 PSI (General Pump chart) | DEWALT DXPA45ST five-tip set (0, 15, 25, 40 degrees and soap) and DXPA45TN turbo nozzle, both 1/4 in quick-connect and rated to 4,500 PSI |
Chart values come from General Pump's nozzle chart. Where a size page shows flow at other pressures, it is calculated with the formula below and labeled as calculated.
The formula
Cat Pumps and General Pump both publish the relationship:[1][2]
nozzle number = GPM x the square root of (4,000 / PSI)
The same sources give the reverse forms: GPM = nozzle number x the square root of (PSI / 4,000), and PSI = (GPM / nozzle number)² x 4,000. Use a paired working value, the flow at that pressure, not a maximum PSI combined with a maximum GPM.
A worked example
Sun Joe's SPX3000 manual (revision MR12) lists 2,030 PSI and 1.76 GPM maximum, and 1,450 PSI and 1.24 GPM rated working output.[3] Use the rated pair:
- 4,000 / 1,450 = 2.759
- The square root of 2.759 = 1.661
- 1.24 x 1.661 = about 2.06
Calculated result: about size 2.06. This is our arithmetic with the published formula, not a figure from Sun Joe, and not a part recommendation. The manual excerpt we verified lists the SPX3000's five tips by angle only, so compare the result with the size stamped on your supplied tips.
Had you used the two maximums instead, the result would be different, which is why the rated pair matters. Greenworks shows the same split: its GPW2303A page in Canada lists a maximum flow of 2.3 GPM and a rated flow of 1.2 GPM.[4]
The angle does not change the size
Cat Pumps states that spray angle does not affect nozzle flow; the flow depends on the nozzle size and the pressure.[1] A 0-degree and a 40-degree tip of the same size flow the same at the same pressure. Choose the size from the formula, then the angles you want.
When pressure drops
Cat Pumps says worn nozzles are the most frequent cause of low pressure, recommends replacing them with the proper size, and warns never to adjust the pressure regulating valve to compensate, because that can over-pressurize and damage the pump.[5] The fix is a new tip of the same size, never a valve change.
Next
- Pressure washer nozzle size chart
- Nozzle size for your pressure washer's PSI and GPM
- Max vs rated PSI and GPM
- Nozzle tips and turbo nozzles: every page
- Nozzle size 2.5
- Nozzle size 3.0
- Nozzle size 3.5
- Nozzle size 4.0
Choose your nozzle size to see the key facts and what fits. Each fact links to its source on the full page.
All nozzle orifice sizes
Shop what this tool points toSee the shortlist
Questions
Which PSI and GPM do I put in the formula?
Your machine's rated, paired working figures, not the headline maximums. Cat Pumps and General Pump note the formula takes flow at that pressure; Sun Joe's SPX3000 manual, for example, lists 1,450 PSI at 1.24 GPM as rated working output.[1][3]
Does a 40-degree tip need a different size than a 15-degree tip?
Not for flow. Cat Pumps states that spray angle does not affect nozzle flow; the flow depends on the nozzle size and the pressure. A set's tips share one size.[1]
My pressure is low. Should I go up or down a size?
First check for wear. Cat Pumps says worn nozzles are the most frequent cause of low pressure and the fix is to replace them with the proper size, and warns never to adjust the pressure regulating valve to make up for them.[5]