Field Capacity & Spray Rate

Units: Saved on this device

Implement & field

Implement / boom width (ft)

Travel speed (mph)

Field efficiency (%)

Includes turns, overlap, refill, etc.

Acres to cover (optional)

Hours available per day (optional)

Fuel rate (gal/hr, optional)

We’ll show if set.

Spray (optional)

Spray mode

Total flow (GPM)

Tank size (gal, optional)

= tank ÷

Results

Theoretical capacity: —

Effective capacity: —

Hours to finish field: — hr

(at hours/day): —

Fuel use (if given): —

Spray rate: —

: —

Tank fills for field: —

Estimates only. Verify with in-field calibration and speed check.

How this calculator works

Enter boom width and travel speed to compute theoretical acres/hour, then apply field efficiency to get effective acres/hour. Add acres to cover and hours/day to plan time. For spraying, either compute GPA from total flow or enter a target GPA and tank size to plan acres per tank and fills.

Rounding: capacities to 1 decimal; hours to 2 decimals; GPA and fuel/acre to 2 decimals.

Formulas

Theoretical ac/hr = (width(ft) × mph) ÷ 8.25
Effective ac/hr = theoretical × efficiency%
Hours to finish = acres ÷ effective
Fuel gal/acre = fuel gph ÷ effective ac/hr
GPA (flow mode) = (5940 × total GPM) ÷ (mph × boom width(in))
Acres per tank = tank(gal) ÷ GPA

Worked example

30 ft, 6 mph, 80% efficiency; total flow 20 GPM; 500 gal tank:

Theoretical = (30×6)/8.25 = 21.8 ac/hr
Effective = 21.8×0.80 = 17.4 ac/hr
GPA = (5940×20)/(6×360) ≈ 5.5 GPA
Acres/tank = 500/5.5 ≈ 90.9 ac

Assumptions & notes

Efficiency represents headland turns, overlap, refill, obstacles, and non-productive time.
GPA formula assumes even nozzle spacing and calibrated speed/pressure; always field-calibrate.
Metric display converts seamlessly (m, km/h, L/min, L/ha, ha); internal math stays in US units for consistency.

Prepared by AgCalculator · Last updated October 27, 2025

FAQ

What is field efficiency?

It captures real-world losses: turns, overlap, refill, and delays. Typical ranges: tillage 70–85%, planting 60–80%, spraying 65–90%.

What’s the formula for acres per hour?

Theoretical = (width(ft) × mph) ÷ 8.25. Effective = theoretical × efficiency%.

How do I calculate spray GPA?

GPA = (5940 × total GPM) ÷ (mph × boom width(in)). Or enter a target GPA to get acres per tank and fills.

Can I use metric units?

Yes — toggle at the top. Outputs switch to ha/hr, L/ha, etc.