Understanding your result
The headline is the tip number, and the sub-line gives the orifice, the fan width, the flow and a warning if the pump is too small. The three figures show the orifice, the fan and whether it fits the pump.
The table lists the material, the orifice range for it, the fan width and its digit, the recommended tip, its flow, the pump verdict and the largest tip the pump supports. When the middle of the material’s range is too big for the pump, the calculator steps down to the largest orifice that fits and says so in the notes.
The tip sets the flow, and the flow sets everything downstream. The sprayer usage calculator uses the same flow table to give trigger minutes and spraying time; the thinning calculator covers the alternative of thinning for a small pump; and the spray versus roll calculator compares the job with rolling.
How we calculate this
The orifice ranges by material are the bands in the sprayer makers’ tip selection charts: about .009 to .013 for lacquers, stains and sealers, .011 to .015 for enamels, .013 to .017 for primers, .015 to .019 for interior latex, .017 to .021 for heavy exterior latex, and .021 to .031 for elastomerics and block fillers. The calculator takes the middle of the band and steps down if the pump cannot supply it. The flow figures, from .009 at 0.09 gpm to .031 at 1.03 gpm, are water at 2,000 psi from the same charts, rounded.
The spray tips guide explains the numbering and the wear, and the film thickness guide explains why thick, high-solids coatings need large orifices.
The assumptions behind the numbers
| Assumption | Value | Where it comes from |
|---|---|---|
| Orifice ranges by material | as listed above | Graco, Titan and Wagner tip selection charts |
| Flow, .015 / .017 / .019 / .021 | 0.24 / 0.31 / 0.38 / 0.47 gpm | The same charts, water at 2,000 psi, rounded |
| Fan width digit | fan ÷ 2, measured at 12 in | The standard tip numbering |
| Pump check | tip flow ≤ pump rating | Sprayer makers’ maximum-tip guidance |
| Default pump | 0.47 gpm | A typical small contractor sprayer |
Assumptions last reviewed October 8, 2026.
The calculator does not model fine-finish (low-pressure) tips, which flow less at the same orifice, hose length and diameter, which limit heavy materials, or paints that the manufacturer specifies a particular tip for; the product data sheet overrides the chart.
Two worked examples
Walls in interior latex
10 in fan, a sprayer rated 0.47 gpm.
- Range for latex: .015 to .019; middle .017
- First digit: 10 ÷ 2 = 5; tip 517, about 0.31 gpm
- The pump can run it, and its largest tip is .021
The same pump with a 6 in fan for lacquer on cabinets: 311, 0.12 gpm.
Elastomeric on a small pump
12 in fan, elastomeric, the same 0.47 gpm sprayer.
- Range: .021 to .031; middle .025 needs 0.67 gpm, too much
- Largest that fits: .021; tip 621, 0.47 gpm
On a 0.27 gpm pump even .021 is too big, and the result says the pump is too small for the material: rent a larger rig.
Where to find your inputs
Material. From the can: lacquer or stain, enamel, primer, latex wall paint, exterior latex, or elastomeric and block filler.
Fan width. About 10 to 12 in for walls, 6 to 8 in for doors and cabinets, 4 in for spindles.
Pump rating. On the sprayer’s label or in its manual, in gallons per minute; the manual often also states the maximum tip size.
Common mistakes
- Choosing the fan by the wall, the orifice by guesswork. The orifice comes from the material.
- A tip bigger than the pump can feed. The fan collapses into tails.
- Turning up the pressure on a worn tip. Replace the tip.
- A wide fan on trim. Most of the paint misses.
- Thinning instead of changing tips. It thins the film too.
- Ignoring the data sheet. Some products specify their tip.
Questions people ask
- What size spray tip for interior latex walls?
- A 515 or 517. That is a 10 in fan with a .015 or .017 in orifice, which flows about 0.24 to 0.31 gallons a minute of water at 2,000 psi and suits most sprayers rated 0.27 gpm and up.
- What do the numbers on a spray tip mean?
- The first digit doubled is the fan width in inches at 12 in from the surface; the last two digits are the orifice diameter in thousandths of an inch. A 517 sprays a 10 in fan through a .017 in orifice; a 317 sprays a 6 in fan through the same orifice, with the same flow.
- What tip for trim and doors?
- A narrower fan with a small orifice, such as a 310, 312 or 412 for enamels and a 411 or 413 with a fine-finish tip for cabinets. The narrow fan puts the paint on the narrow surface instead of beside it.
- What tip for elastomeric or block filler?
- A large orifice, .021 to .031, and a pump built for heavy materials. Many small sprayers top out at .019 or .021 and cannot run these products well.
- How do I know if my pump can run a tip?
- Compare the tip's flow with the pump's rating. A tip that flows more than the pump delivers cannot hold pressure, and the fan collapses into tails. The calculator flags it and names the largest tip the pump supports.
- When should I replace a spray tip?
- When the fan narrows, the edges grow heavy tails, or you have to raise the pressure to get a clean pattern. Those are signs the orifice has worn larger, which wastes paint and leaves a heavier film in the middle of the fan.