Agricultural Tank Mix & Spray Calibration Calculator
Spray Setup
gal
GPA
ft
mph
in
Products
Product 1
Formulation
Nozzle Flow Rate0.404 GPM
Acres per Tank20.0
Product Amounts per Tank
| Product | Amount/Tank↕ | Unit | Cost/Acre↕ |
|---|---|---|---|
| Herbicide A | 320.00 | oz/ac | - |
W-A-L-E-S Mixing Order
| Step | Category | Products |
|---|---|---|
| W | Water (fill tank 50-75%) | - |
| A | Agitation (start agitation) | - |
| L | Liquid flowables | Herbicide A (320 oz/ac) |
| E | Emulsifiable concentrates | Herbicide A (320 oz/ac) |
| S | Surfactants & Solubles | - |
This agricultural spray calibration calculator turns a target application rate into the practical numbers an operator needs: the nozzle flow rate in gallons per minute, the acres a full tank covers, and how much of each product to add per tank. It also lays out a W-A-L-E-S tank-mixing order so incompatible formulations go in safely. Enter your sprayer setup and product rates to calibrate before you ever leave the shed.
Formula
GPM = (GPA × speed_mph × spacing_in) ÷ 5940 ; acres/tank = tank_gal ÷ GPA
- GPM
- Required flow per nozzle in gallons per minute
- GPA
- Target application rate in gallons per acre
- speed_mph
- Sprayer travel speed in miles per hour
- spacing_in
- Nozzle spacing along the boom in inches
- 5940
- Unit-conversion constant for the GPA flow equation
- tank_gal
- Spray tank capacity in gallons
How it works
- Enter the tank size in gallons, the target application rate in gallons per acre (GPA), your travel speed in mph, and the nozzle spacing in inches.
- Add each product with its rate per acre, unit, formulation type (liquid, dry, or soluble), and optional cost per unit.
- The calculator derives the required nozzle flow rate from GPA, speed, and spacing, computes acres covered per tank, scales every product to a per-tank amount, and sorts the products into the W-A-L-E-S mixing sequence.
Worked example
A 300-gallon tank at 15 GPA, 8 mph, 20-inch nozzle spacing, applying 32 oz/ac of a liquid product.
- Nozzle flow: (15 × 8 × 20) ÷ 5940 = 2400 ÷ 5940 = 0.404 GPM.
- Acres per tank: 300 ÷ 15 = 20 acres.
- Product per tank: 32 oz/ac × 20 ac = 640 oz.
Each nozzle needs about 0.404 GPM, the tank covers 20 acres, and you add 640 oz of the liquid product per tank.
Frequently asked questions
- What does the W-A-L-E-S mixing order mean?
- W-A-L-E-S stands for Water, Agitation, Liquid flowables, Emulsifiable concentrates, and Surfactants/solubles. Adding products in that sequence with the tank half-full and agitation running helps prevent clumping and incompatibility problems.
- How is nozzle flow rate calculated?
- The calculator uses GPM = (GPA × speed × nozzle spacing) ÷ 5940, where 5940 is the standard conversion constant. This tells you the flow each nozzle must deliver to hit your target gallons per acre at your chosen speed and spacing.
- How many acres will one tank cover?
- Divide the tank capacity by the target gallons per acre. A 300-gallon tank applied at 15 GPA covers 300 ÷ 15 = 20 acres, which also sets how much of each product to load per tank.
- Why does travel speed matter for calibration?
- Faster travel means each nozzle passes over more ground per minute, so it must deliver a higher flow to keep the same gallons per acre. The flow equation scales directly with speed, which is why recalibrating after a speed change is essential.