How do you calculate acres per hour?

Multiply your working width in metres by your ground speed in kilometres per hour, divide by 10 to get hectares per hour at 100 percent efficiency, then multiply by your field efficiency. Multiply hectares per hour by 2.471 to convert to acres per hour. A 3 metre implement at 8 km/h and 80 percent efficiency covers 1.92 hectares, or about 4.74 acres, each hour.

What is field efficiency?

Field efficiency is the share of working time actually spent covering new ground. Turning at the headlands, overlapping passes, refilling sprayers or seed boxes and clearing blockages all eat into it. Typical values are 70 to 90 percent, with mowing and cultivating near the top of that range and spraying or drilling with frequent refills near the bottom.

How many acres can a tractor cover in an hour?

It depends almost entirely on implement width and speed. A 3 metre mower at 8 km/h and 80 percent efficiency covers about 4.7 acres an hour, while a 12 metre sprayer at 16 km/h and 70 percent efficiency covers about 33 acres an hour. Use your own width, speed and efficiency for a realistic figure.

Acres per Hour Calculator

This acres per hour calculator works out how much ground you actually cover in an hour of mowing, spraying, cultivating, drilling or topping, based on your implement width, ground speed and field efficiency. Enter the working width of the implement in metres, your typical speed in kilometres per hour, and an efficiency figure that allows for turning at the headlands, overlapping passes and refilling, and the calculator returns your real work rate in both acres and hectares per hour. Add the size of the paddock you are about to start and it also tells you how long the job will take, which is handy for quoting contract work, planning a spray window before the wind gets up, or deciding whether you can finish before dark. The theoretical rate at 100 percent efficiency is shown alongside so you can see how much time the turns and stoppages cost you. Contractors, lifestyle block owners and farmers all use the same maths: width times speed gives ground covered, and efficiency scales it back to reality. If you think in feet and miles per hour, convert them first, then read your answer in whichever unit your paddocks are measured in.

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Working width of implement

Ground speed

km/h

Field efficiency

Paddock size

acres

4.74

acres covered per hour

Hectares per hour1.92 ha

Time to cover 20 acres4 h 13 min

At 100% efficiency5.93 acres/hr

Field efficiency allows for headland turns, overlap and refilling; 70 to 90 percent is typical. Estimate only: actual rates vary with paddock shape, obstacles and conditions.

How it works

Working width multiplied by ground speed gives the strip of ground you cover: a width in metres times a speed in kilometres per hour equals thousands of square metres per hour, and dividing by 10 converts that to hectares per hour. Multiplying by field efficiency scales the theoretical rate down to what you achieve once turning, overlap and refilling are counted, and multiplying hectares by 2.4710538 converts to acres. The time for the paddock is simply its area divided by your effective work rate in the same unit.

Worked example

You are topping with a 3 metre mower at 8 km/h and expect 80 percent field efficiency. The theoretical rate is 3 x 8 / 10 = 2.4 hectares per hour, and at 80 percent efficiency the effective rate is 1.92 hectares per hour, which is 1.92 x 2.4710538, or about 4.74 acres per hour. A 20 acre paddock therefore takes 20 / 4.74, which is about 4 hours 13 minutes. At 100 percent efficiency the same outfit would manage about 5.93 acres per hour, so the turns and stoppages are costing you roughly one acre every hour.

Related calculators

Acreage Calculator: land area in acres and hectares.
Acres to Hectares Converter: quick unit conversion.
Fuel Consumption Calculator: fuel used for the job.
Speed Calculator: speed, distance and time.
Hours Calculator: add up working hours.

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