Corn Irrigation Calculator
Calculate irrigation water volume in gallons and acre-feet based on acres irrigated, water depth applied, and system efficiency.
Irrigation Inputs
Calculate water volume needed
Take multiple samples from different field locations and average them for the most accurate results. Avoid border rows and unusual spots.
All calculations use USDA-standard formulas. No registration required, works on mobile, tablet, and desktop.
What Is a Corn Irrigation Calculator?
A corn irrigation calculator helps you determine the volume of water needed to irrigate a field based on acreage, water depth applied, and system efficiency. Whether you're using a center pivot, linear move, or flood irrigation, knowing your water volume is essential for pump sizing, energy planning, and water rights management.
Corn uses 22-30 inches of water per season, depending on climate and yield level. Peak water use during tasseling and grain fill can reach 0.35 inches per day in hot, windy conditions. Scheduling irrigation to match crop demand prevents yield loss from drought stress.
This calculator handles the conversion between inches of water, gallons, and acre-feet — the three common units used in irrigation planning. System efficiency accounts for losses to evaporation, deep percolation, and runoff.
Irrigation Volume Formulas
Key conversion factors:
- 1 acre-inch = 27,154 gallons
- 1 acre-foot = 12 acre-inches = 325,851 gallons
- 1 inch on 1 acre = 27,154 gallons
Calculation:
Gross gallons = Acres × Inches applied × 27,154
Net gallons = Gross × Efficiency %
Acre-feet = (Acres × Inches) ÷ 12
Example
130 acres with 1.5 inches applied at 85% efficiency:
Gross = 130 × 1.5 × 27,154 = 5,295,030 gallons
Net = 5,295,030 × 0.85 = 4,500,776 gallons
Acre-feet = (130 × 1.5) ÷ 12 = 16.25 ac-ft
Corn Water Use by Growth Stage
Total seasonal water use: 22-30 inches. Critical periods: tasseling through grain fill (early July through August in Corn Belt).
Irrigation System Efficiencies
Center Pivot (95%)
Most efficient for corn. 130-acre pivot covers 1/4 section. LEPA nozzles reach 95-98% efficiency.
Linear Move (90%)
Used on rectangular fields. Similar efficiency to pivot but more infrastructure.
Drip/Trickle (90%)
Not common for corn but very efficient. High capital cost, best for high-value crops.
Furrow/Flood (60-75%)
Traditional but less efficient. Significant losses to evaporation and deep percolation.
Frequently Asked Questions
Everything you need to know about corn yield calculation
Corn needs 22-30 inches of water per season, equivalent to 600,000-815,000 gallons per acre. Peak daily use during tasseling can reach 0.35 inches (9,500 gallons/ac/day). Irrigation supplements rainfall to meet total water demand.
One acre-inch of water equals 27,154 gallons. One acre-foot (12 acre-inches) equals 325,851 gallons. To calculate: acres × inches × 27,154 = total gallons.
Irrigation frequency depends on soil water-holding capacity, weather, and growth stage. Sandy soils need irrigation every 2-3 days; clay soils every 5-7 days. During peak water use (tasseling), apply 1-1.5 inches per week. Use soil moisture sensors for accurate scheduling.
Center pivot irrigation is the most efficient and cost-effective system for corn in the US. Modern pivots with LEPA (Low Energy Precision Application) nozzles achieve 95%+ efficiency. A 1/4-mile pivot covers 130 acres and costs $60,000-100,000 installed.
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