How many acres per hour?
Type the working width, the ground speed and the field efficiency. The acres per hour calculator gives the field capacity in acres and hectares per hour, the theoretical capacity, and the hours a field takes.
- Field capacity (acres per hour)
- 9.7
You can cover about 9.7 acres per hour.
- Field capacity (hectares per hour)
- 3.92
- Theoretical capacity (acres per hour)
- 12.12
Field capacity (acres per hour): 9.7. You can cover about 9.7 acres per hour.
Field capacity (acres per hour) by field efficiency
How to calculate
Computes the acres per hour (effective field capacity) of a tractor, mower, sprayer or planter from its working width, ground speed and field efficiency, with hectares per hour and the hours a field takes.
Example with the default inputs (Working width 20 ft, Ground speed 5 mph, Field efficiency 80%): You can cover about 9.7 acres per hour.
Method: Acres per hour = speed × width × field efficiency ÷ 43,560 sq ft; in US units, mph × ft × efficiency ÷ 8.25. Hours = field size ÷ acres per hour.
- The width is the effective width, without overlap; the speed is the working speed in the field.
- Field efficiency covers time lost to turns, overlap, filling, emptying and small repairs; Iowa State’s example uses 83%.
- 1 acre = 43,560 sq ft and 1 mile = 5,280 ft, so mph × ft ÷ 8.25 gives acres per hour.
Worked examples
Each example is checked against the calculator on every build.
- Working width 30 ft, Ground speed 5 mph, Field efficiency 83% gives Field capacity (acres per hour) 15.090909, Theoretical capacity (acres per hour) 18.181818.Source: Iowa State University Extension, Ag Decision Maker A3-24, Estimating the Field Capacity of Farm Machines (field capacity in acres per hour = speed in mph × width in feet × field efficiency ÷ 8.25, where 8.25 = 43,560 ÷ 5,280; a 30-foot implement at 5.0 mph and 83% field efficiency covers about 15 acres per hour), https://www.extension.iastate.edu/AGDM/crops/html/a3-24.html (retrieved 2026-10-03)
- Working width 20 ft, Ground speed 6 mph, Field efficiency 80%, Field size 160 ac gives Field capacity (acres per hour) 11.636364, Hours for the field 13.75.Source: Iowa State University Extension, Ag Decision Maker A3-24, Estimating the Field Capacity of Farm Machines (field capacity in acres per hour = speed in mph × width in feet × field efficiency ÷ 8.25, where 8.25 = 43,560 ÷ 5,280; a 30-foot implement at 5.0 mph and 83% field efficiency covers about 15 acres per hour), https://www.extension.iastate.edu/AGDM/crops/html/a3-24.html (retrieved 2026-10-03)
- Working width 19.69 ft, Ground speed 6.214 mph, Field efficiency 75% gives Field capacity (hectares per hour) 4.5, Field capacity (acres per hour) 11.119742.Source: Iowa State University Extension, Ag Decision Maker A3-24, Estimating the Field Capacity of Farm Machines (field capacity in acres per hour = speed in mph × width in feet × field efficiency ÷ 8.25, where 8.25 = 43,560 ÷ 5,280; a 30-foot implement at 5.0 mph and 83% field efficiency covers about 15 acres per hour), https://www.extension.iastate.edu/AGDM/crops/html/a3-24.html (retrieved 2026-10-03)
How it works
With the ground speed S, the working width W and the field efficiency E (percent):
- Theoretical capacity = S × W ÷ 43,560 sq ft per acre; in US units, S (mph) × W (ft) ÷ 8.25.
- Field capacity (acres per hour) = theoretical capacity × E ÷ 100.
- Hectares per hour = S × W × E ÷ 100 ÷ 10,000 m²; 1 acre = 4,046.8564224 m².
- Hours for the field = field size ÷ field capacity; shown only when a field size is typed.
Rules. The width is from 1 cm to 100 m, in ft, in or m. The speed is from 0.01 m/s to 50 m/s (0.036 to 180 km/h), in mph or km/h. The field efficiency is from 1% to 100%. The field size, when typed, is above 0 and at most 1,000,000,000 m².
Exact arithmetic. Typed values are exact decimals (1 ft = 0.3048 m, 1 mph = 0.44704 m/s, 1 km/h = 5/18 m/s exactly). Results round once, for display.
Output format. Acres and hectares per hour and hours show 2 decimals. In Metric, the page heads the result with hectares per hour.
Worked examples by hand
Iowa State’s example: 30 ft at 5 mph and 83%. Theoretical = 30 × 5 ÷ 8.25 = 18.18 acres per hour. Field capacity = 18.18 × 0.83 = 15.09 acres per hour.
A 20 ft mower at 6 mph and 80%, 160-acre field. 20 × 6 × 0.80 ÷ 8.25 = 11.64 acres per hour. Hours = 160 ÷ 11.636 = 13.75 hours.
A 6 m sprayer at 10 km/h and 75%. 10 km/h = 10,000 m per hour; 6 × 10,000 × 0.75 = 45,000 m² per hour = 4.5 ha per hour = 4.5 ÷ 0.40469 = 11.12 acres per hour.
Other questions people ask
How do I calculate acres per hour?
Multiply the speed in miles per hour by the working width in feet and the field efficiency, then divide by 8.25. A 30-foot implement at 5 mph and 83% covers 30 × 5 × 0.83 ÷ 8.25 = 15.1 acres per hour.
Where does 8.25 come from?
An acre is 43,560 sq ft and a mile is 5,280 ft. A 1-foot strip one mile long is 5,280 sq ft, and 43,560 ÷ 5,280 = 8.25. So mph × feet ÷ 8.25 is acres per hour.
What is field efficiency?
The share of time the machine works at its full width. Turning at the ends, overlapping passes, filling seed or spray tanks, emptying and small repairs all take time. Iowa State’s example uses 83%; your own records give the best number.
What width should I use?
The effective width that is new ground on each pass, without overlap. A 60-inch mower deck that overlaps the last pass by 4 inches covers 56 inches, not 60.
How long will my field take?
Type the field size. The hours are the field size ÷ the acres per hour: 160 acres at 11.64 acres per hour take 13.75 hours.
Can I use metric units?
Yes. Pick metres and km/h, and the result heads with hectares per hour. A 6 m sprayer at 10 km/h and 75% covers 4.5 ha per hour.