Pump Sizing Calculator

Work out the flow and pressure your sprayer or transfer setup really needs, then see which pumps we stock will cover it.

1

What is the pump for?

Boom sprayerField, turf or roadside boom with a rate controller
Spray gun / handgunSpot spraying, trees, livestock, high pressure
Transfer / fillFilling the sprayer, tender, moving water or fertilizer
2

Your setup

Flow is set by your tips and ground speed. Pressure is what the tips need plus what the plumbing eats on the way there.

Size for your fastest speed — that's when the tips need the most flow. Don't know your tip pressure? The nozzle selector tells you the pressure for your tip size at that speed. Pulse-width (PWM) systems: use the pressure you set the system to, usually 40–60 psi.
Agitation, plumbing and margin (defaults are typical)
Jet agitators need pressure too — this assumes they run off the same pump at 30–40 psi. Plumbing loss covers strainers, control valves, flow meter and 50+ ft of hose; add more for long booms or small hose. A 20% flow margin is added so the controller has room to work.
3

How will it be driven?

Pick everything that's an option on your rig — we'll show the best match for each.

Hydraulic PTO (540 / 1000 rpm) Gas engine 12-volt Electric motor / pedestal
Required flow = tips × GPM per tip at your top speed, plus agitation, plus a 20% controller margin. Required pressure = tip pressure plus plumbing loss. Pump performance is from manufacturer published maximums (and curves where published); rows marked "approx." are estimated and we'll confirm them for you before you buy. Hydraulic pumps need the oil flow listed — short them and they won't make rated pressure.

How to size a sprayer pump

A pump is sized on two numbers at once: the gallons per minute the whole system draws, and the pressure it has to make while delivering them. Get the flow right and the pressure wrong and the tips never reach their rated pattern; get the pressure right and the flow short and the controller can't hold rate at speed. The calculator above works both numbers from your boom, speed and tips, adds agitation and plumbing losses, and then checks each pump we sell against that operating point — not just against its headline maximum.

Boom GPM = tips × GPM per tip at top speed
Agitation GPM ≈ 5% of tank volume per minute (jet agitation)
Pump GPM needed = (boom + agitation) × 1.2
Pump PSI needed = tip pressure + plumbing loss (15–25 psi typical)

Why the headline maximum isn't the number

A centrifugal pump's "114 GPM / 130 PSI" rating is two different points on its curve: 114 GPM at nearly zero pressure, 130 PSI at nearly zero flow. At a real operating point — say 60 GPM at 65 psi — the same pump might be using most of what it has. That's why the results show where your setup lands on each pump's curve and how much headroom is left, and why a pump with "more GPM" isn't always the better pick.

Centrifugal, roller or diaphragm?

Type Best for Pressure Notes
Centrifugal Boom sprayers, transfer, agitation Up to ~150 psi High volume, tolerates abrasives, flow falls as pressure rises. Hydraulic, gas or PTO-gearbox driven.
Roller Small PTO sprayers, 3-point and pull-type booms, handguns Up to 300 psi Positive displacement: flow set by rpm. Needs a bypass/relief. Wears with abrasives.
Diaphragm Handguns, orchard, high pressure, harsh chemicals 290–580 psi Positive displacement, oil-backed, needs a pressure regulator and a surge tank. Long life with wettable powders.
12-volt diaphragm ATV/UTV sprayers, spot sprayers, small booms 45–60 psi Demand switch, 1.8–5.3 GPM. Great for small rigs; not for big booms.

Hydraulic pumps: match the oil

A hydraulic-motor pump is rated at a specific oil flow — 7, 13, 16 or 17 GPM for the common Hypro and Ace models. Give it less and it turns slower and makes less pressure; give an open-center model more than it can bypass and you cook the oil. Know whether your tractor is open-center or closed-center (load-sensing) and what flow the remote delivers before you choose; the results list the oil requirement next to each hydraulic pump.

Common questions

What size pump do I need for a 60-foot boom?

At 20-inch spacing that's 36 tips. At 15 GPA and 14 mph each tip needs 0.71 GPM, so the boom draws 25 GPM; add jet agitation for a 500-gallon tank (25 GPM) and a 20% margin and you want about 60 GPM at 65–70 psi. A Hypro 9303C-HM1C or Ace FMC-150 class pump covers that with room to spare; a 12-volt pump does not.

How much agitation do I need?

Rule of thumb for jet (hydraulic) agitation is 5% of tank volume per minute — 25 GPM for a 500-gallon tank — more for wettable powders and dry flowables, less for straight solutions. Mechanical paddle agitators need none from the pump. The tool adds this to the boom flow.

Can a 12-volt pump run a boom?

Small ones. A 5.3 GPM / 60 psi SHURflo covers roughly a 10–12 ft boom at low rates. Beyond that you're into a gas-engine centrifugal, a roller pump on a PTO, or hydraulics.

Should I size for pressure at the pump or at the tip?

At the tip, then add what the plumbing loses. Strainers, section valves, a flow meter and 50 ft of hose typically cost 10–25 psi. If you have a gauge at the boom and one at the pump, the difference is your real number — enter it under plumbing loss.

My pump is already on the sprayer — do I need a new one?

Maybe not. Run the catch test on the calibration page; if the boom holds pressure at your top speed with agitation on, the pump is fine. If pressure sags as you speed up, the pump is at the edge of its curve. Repair kits and parts for your existing pump are in the Pump Finder.

Related tools

Pump finder (identify, parts & kits) · Nozzle selector · Sprayer calibration · Tank mix calculator · All pumps & drives

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