Grounds ToolkitMowing and Production
How Many Acres Can This Mower Cover Per Hour?
Enter your mower's deck width, type, and the property's terrain. This estimates a realistic production rate, not the raw manufacturer number, along with a likely range and the math behind it.
How this is calculated
The formula is the same one mower manufacturers and the OPEI use: deck width in inches, times speed in miles per hour, times (1 minus an overlap allowance), divided by 99. That gives a raw geometric rate. A field efficiency factor, 80% by default, is then applied to account for turning, trimming interruptions, and obstacles that the raw formula doesn't capture. See the Methodology page for how defaults across the toolkit are chosen and sourced.
Worked example
A 42-inch deck riding mower at its typical 4 mph, on an open lawn, uses a 10% overlap allowance. Raw rate: 42 × 4 × 0.9 ÷ 99, about 1.53 acres per hour. Applying 80% field efficiency brings that to about 1.22 acres per hour, or roughly 49 minutes per acre.
Common mistakes
- Using a mower's top rated speed instead of a realistic mowing speed.
- Ignoring overlap, which understates real time by 10 to 20 percent.
- Treating this as total service time. It's mowing only, trimming and cleanup are separate.
Frequently asked questions
What does field efficiency mean in this calculation?
Field efficiency accounts for turning, trimming interruptions, and obstacles that slow down real mowing compared to the raw geometric formula. This calculator uses 80% as a typical default, editable in advanced settings.
Why does terrain change the estimate?
Trees, beds, and narrow strips require more overlap between passes to avoid missed grass, which lowers effective coverage. Open lawn uses a 10% overlap allowance, obstructed terrain uses 20%.
How is the acres-per-hour formula derived?
It is the industry-standard formula used by mower manufacturers: deck width in inches, times speed in mph, times (1 minus overlap), divided by 99. The 99 comes from converting inches and miles into acres.
Does this include time for trimming and edging?
No. This calculator estimates mowing production only. Trimming, edging, and cleanup add additional time on top of this rate.
What if I already know my actual mowing speed?
Enter it under advanced settings. The mower-type default is a typical midpoint speed for that class of mower, your actual speed will usually be more accurate.
Next decision
Once you have a production rate, the next question is usuallyhow long a specific property will take your crew, including trimming and cleanup, not just mowing.