For compressed air sprayer calibration, what is the size of the calibration square to mark?

• A. 18.5 ft x 18.5 ft
• B. 20 ft x 20 ft
• C. 15 ft x 15 ft
• D. 10 ft x 10 ft

Answer: (A)

Calibration of a compressed air sprayer relies on measuring how much spray is applied over a defined ground area so you can convert that into gallons per acre. The standard approach uses a square laid out on the ground, and its size is chosen to make the math straightforward when converting to acres. An 18.5-foot by 18.5-foot square gives a test area of 342.25 square feet, which is about 0.00785 acres. This small, practical area keeps measurements easy to handle in the field while providing a clean conversion factor (gallons per test area can be scaled to gallons per acre) for determining the correct application rate. So the designated calibration square size is 18.5 ft on each side. Other sizes would complicate the calculation or yield awkward conversion factors.