Mowing Time Calculator

How long a lawn takes to mow comes down to four things: how much grass there is, how wide the deck is, how fast you can mow and still get a clean cut, and how much of your time goes into turning around trees and beds. Enter yours below. To work backward, add the number of minutes you want to spend and the calculator gives the minimum deck width.

How the calculation works

Area. Enter acres, or square feet (43,560 sq ft = 1 acre). Count only the grass you mow, not the house, drive and beds.
Acres per hour. acres per hour = mowing speed (mph) x 5,280 x deck width (ft) x (1 – overlap) x 0.8 / 43,560. The 0.8 field efficiency covers turns, edges and slowing down at the ends of passes.
Obstacles. Multiply the area by 1.0 for an open lawn, 1.2 for some trees and beds, or 1.45 for many obstacles and tight corners.
Time. minutes = area x obstacle factor / acres per hour x 60.
Reverse mode. deck width (in) = area x obstacle factor x 43,560 x 12 / (mph x 5,280 x (1 – overlap) x 0.8 x hours), rounded up to a common deck size.

Worked example

Two open acres with a 48 in residential zero-turn at about 6 mph and 10% overlap: 6 x 5,280 x 4 ft x 0.9 x 0.8 / 43,560 = 2.09 acres per hour, so 2 / 2.09 x 60 = about 57 minutes. Add some trees and beds (factor 1.2) and it becomes about 69 minutes.

Want the same two open acres done in an hour at the same speed? The minimum deck works out to 45.8 in, so a 46 in deck or wider. A lawn tractor at about 5 mph would need roughly a 55 in deck to finish in the same time.

Assumptions and limits

Mowing speeds are planning figures, not top speeds: a zero-turn’s maximum forward speed is for getting around, and most people mow slower to keep a clean cut, especially in thick or wet grass. Bagging, steep ground and long grass all add time. Battery mowers also need enough rated acres per charge for your lawn.

Mowing safety

Read the manual, keep children and pets out of the yard while you work, wear eye and hearing protection and sturdy footwear, and never exceed the slope rating of your machine. Refuel only with the engine off and cool. See CPSC lawn mower safety. Read our Safety Disclaimer.

Frequently Asked Questions

How long does it take to mow 1 acre with a riding mower?

With a 42 in lawn tractor at about 5 mph and some trees, plan on roughly 45 to 50 minutes. A 48 in zero-turn on an open acre takes closer to 30 minutes. Enter your own lawn above for a better estimate.

What size deck do I need for 2 acres?

Most people mowing 2 acres look at 46 to 54 in decks. A 48 in zero-turn covers two open acres in about an hour; with lots of trees, a wider deck or a faster mower keeps it near that.

Does a wider deck always save time?

Only if you can use it. A wide deck that does not fit through gates or between trees forces you to trim more by hand, and a heavy wide mower may need to slow down on slopes. Match the deck to the open parts of your lawn.

Why is my real mowing time longer than the result?

Thick or wet grass, bagging, slopes, emptying a bagger and mowing slower around kids’ toys or flower beds all add time. Use the many-obstacles setting or a lower speed to see the effect.

Is a zero-turn faster than a lawn tractor?

Usually, because it mows at a higher speed and turns in place at the end of each pass. On hills, a lawn tractor’s steering wheel and front-wheel steering give steadier control. See zero-turn vs lawn tractor.

Mower guides by size

Not sure which type to buy? Try the Mower Matcher or browse guides by acreage.