Guide · Nozzle tips and turbo nozzles
Pressure washer nozzle sizes: the orifice number, not the color
A nozzle carries two numbers: its size (flow in GPM at 4,000 PSI) and its spray angle. A chart of sizes 2.5 to 4.0 with orifice and flow, from pump-maker charts.
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Short answer
A pressure washer nozzle has two numbers. The size number is the nozzle's flow in GPM at 4,000 PSI, and the angle (0, 15, 25 or 40 degrees) is the width of the fan. A "4-25" tip is size 4 with a 25-degree fan. The color only tells you the angle, and only in that maker's scheme.
Two numbers on every tip
Cat Pumps explains that a nozzle number equals the nozzle's flow in GPM at 4,000 PSI, and that the spray angle is a separate figure.[1] Both are stamped on the nozzle, so a "4-25" is size 4 with a 25-degree fan.[1]
The size number is what decides whether a tip suits your machine. The angle only decides how wide the spray spreads.
Angle does not change flow
Cat Pumps states that spray angle does not affect nozzle flow; the flow depends on the nozzle size and the pressure.[2] A size 3.0 tip passes the same flow at 15 degrees as at 40 degrees. Switching from one angle to another in the same set does not ask more water of the pump.
The chart
General Pump's nozzle chart lists each size with an equivalent orifice diameter in inches. Size 2.5 is 0.039 in and flows 2.17 GPM at 3,000 PSI.[3] Size 4 is 0.052 in and flows about 3.46 GPM at 3,000 PSI and 4.00 GPM at 4,000 PSI.[3] The same size 4 flows about 2.83 GPM at 2,000 PSI.[3] Cat Pumps gives a 3.0 nozzle as a 0.043 in orifice flowing 3.0 GPM at 4,000 PSI.[1]
Cat Pumps and General Pump both publish the relationship behind the chart: nozzle number = GPM x √(4,000 / PSI), which also gives GPM = nozzle number x √(PSI / 4,000).[2][3] The cells marked "calc." below are calculated with that formula and rounded; the others are chart values.
| Size | Orifice (in) | GPM at 2,000 PSI | GPM at 3,000 PSI | GPM at 4,000 PSI |
|---|---|---|---|---|
| 2.5 | 0.039 | 1.77 (calc.) | 2.17 | 2.50 (calc.) |
| 3.0 | 0.043 | 2.12 (calc.) | 2.60 (calc.) | 3.00 |
| 3.5 | not in our sources | 2.47 (calc.) | 3.03 (calc.) | 3.50 (calc.) |
| 4.0 | 0.052 | 2.83 | 3.46 | 4.00 |
These are reference-chart and formula values, not the measured output of any machine. They show one thing clearly: the same tip passes less water at lower pressure.
Each size has its own page with the machines and tips that use it: size 2.5, size 3.0, size 3.5 and size 4.0.
Sizes by maker
Makers sell the same five angles in different sizes, so the size is part of the model name you buy.
- DEWALT sells five-tip 1/4 in quick-connect sets in two versions: the DXPA34ST in size 3.0, rated to 3,400 PSI, and the DXPA45ST in size 4.0, rated to 4,500 PSI. Each has 0, 15, 25 and 40-degree tips and a soap tip.[4][5]
- Active says its Active 2.0 ships with 0, 15, 25 and 40-degree nozzles in size 3.7.[6]
- Champion lists nozzle codes 00028, 15028, 25028 and 40028 for the 0, 15, 25 and 40-degree tips of its 100384.[7] The manual does not explain what the digits mean, so do not read a size from the code alone; ask Champion or read the stamp on the tip.
Colors are maker names, not sizes
Generac's manual names its quick-connect tips by color: red for blast, green for clean, white for wash and black for detergent.[8] Westinghouse's PWEXT kit marks red 0, yellow 15, green 25, white 40 and black 65 degrees.[9] Neither color scheme says anything about size. A red tip from a size 3.0 set and a red tip from a size 4.0 set are different nozzles. More on the angles in nozzle colors and spray angles.
Finding the size you have
- Read the stamp on the tip. Cat Pumps says the size and angle are both stamped on it.[1]
- If the stamp is worn or missing, check the manual's parts list or the maker's accessory page.
- If you still cannot tell, ask the maker rather than guessing from the color.
Then compare the size with your machine's rated output: which nozzle size fits your PSI and GPM walks through the math, and the nozzle size finder does it for you.
Approved tip sets by size
Picks that fit3 products
Pick the size, not the color. SIMPSON 80145 is the size 3.0 set; SIMPSON 80146 and DEWALT DXPA45ST are size 4.0 sets.
More on choosing
All three are five-tip 1/4 in quick-connect sets. Match the size to your machine's rated output and keep the set's PSI rating above your machine's. On Amazon, check that Ships from / Sold by is Amazon.com or the brand.
SIMPSON five-tip set, smaller of two sizes
SIMPSON 80145 1/4 in quick-connect nozzle set, 5 tips, size 3.0, 3,600 PSI
SIMPSON five-tip set, larger of two sizes
SIMPSON 80146 1/4 in quick-connect nozzle set, 5 tips, size 4.0, 4,500 PSI
Five-tip set in size 4.0
DEWALT DXPA45ST 4,500 PSI quick-connect spray tips, 5 tips, size 4.0, stainless steel
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Questions
What do the numbers on a pressure washer nozzle mean?
Cat Pumps says two figures are stamped on a nozzle: the size number and the spray angle. A '4-25' is size 4 with a 25-degree fan, and the size number is the nozzle's flow in GPM at 4,000 PSI.[1]
Are all red nozzles the same?
No. Color is a maker's naming convention for the spray angle, not the size. Two red tips from sets in different sizes pass different flows at the same pressure, so read the size number instead.[8][1]
Does a 15-degree nozzle use more water than a 40-degree one?
No. Cat Pumps states that spray angle does not affect nozzle flow; flow depends on the nozzle size and the pressure.[2]