Fertilizer Orifice Plate Calculator
Tell us your setup and target rate — we'll match it against what we actually stock.
One tool, three modes: broadcast spray tips · fertilizer orifice plates & VR caps · SJ3 liquid deicer tips. Switch with the tabs below.Nozzle & Orifice Selector
Tell us your setup and target rate — we'll match it against what we actually stock.
How to size a fertilizer orifice plate
Liquid fertilizer runs through a stainless TeeJet CP4916 orifice plate instead of a spray tip, and the flow chart on the package is for water. That is the trap: 28% UAN weighs 10.65 lb/gal, 32% UAN weighs 11.06, and 10-34-0 weighs 11.65, and a heavier liquid flows slower through the same hole. Use the water chart straight and you will under-apply by 10–15%.
Step 1: Flow per orifice
Effective spacing is your row spacing divided by the number of nozzles per row — 30-inch rows with two nozzles per row is 15 inches. For example, 15 GPA of 28% at 6 mph on 30-inch rows with one nozzle needs 0.45 GPM of product per orifice.
Step 2: Correct for the weight of the solution
For 28% UAN the factor is 1.13, so that 0.45 GPM of product means finding 0.51 GPM on the water chart. The calculator above does both steps, then picks plates that land in the middle of the 5–60 psi chart rather than at the edges where flow is hard to hold, and tells you which tip strainer mesh to run so the plate does not plug.
Or cover a wide speed range with one VR cap
If your rate controller has to hold a rate as ground speed changes — corn sidedress, y-drop work, contour fields — a TeeJet SJ7A-VR or SJ3-VR variable-rate StreamJet cap opens further as pressure rises and covers 2–3× the flow range of a fixed plate in one part, with no plate swaps. The calculator shows the speed window each VR size covers at your rate.
Common questions
Can I use a spray tip chart for 28% or 32% UAN?
Only after correcting for weight. 28% UAN is about 28% heavier than water, so a plate flows roughly 12% less UAN than the water chart says. The calculator applies that correction for you — choose your solution from the list or enter a custom weight.
What orifice plate do I need for 10 GPA of 32%?
It depends on speed and row spacing. At 5 mph on 30-inch rows, 10 GPA needs about 0.25 GPM of product per orifice — a #39 plate around 30 psi, or a #43 around 20 psi. Enter your numbers above for the sizes we have on the shelf.
Which tip strainer goes with which plate?
Orifice 15 and smaller: 200 mesh. 16–39: 100 mesh. 40–70: 50 mesh. 72 and larger: no strainer needed. Always insert the plate with the numbered side facing the outlet.
Fixed plate or VR cap?
A fixed CP4916 plate is cheaper and fine when your speed is steady. A VR cap is worth it when speed swings more than about 30% in a pass, or when one rig runs several rates. Both are in stock in Spokane.
Still not sure?
Bring us the rate, the speed, the row spacing and the product, and we'll sort it out on the phone in five minutes. This same tool also sizes broadcast spray tips and SJ3 liquid deicer tips — use the tabs at the top.
Call (509) 838-2209