Formula for calculating time to mow

Discussion in 'Lawn Mowing' started by billc, Mar 7, 2004.

  1. billc

    billc LawnSite Member
    Messages: 119

    Does anyone here have a spreadsheet that calculates how long it should take to mow a lawn based on:

    square footage
    speed of mower
    size of deck

    IOW - a 10,000 sq ft lawn mowed with a 52" eXmark traveling at 8 mph should take how long?

    I know - sounds like a dreaded story problem from high school! I've tried to figure it out but smoke starts coming out of my ears!
  2. Mikes Lawn Landscape

    Mikes Lawn Landscape LawnSite Senior Member
    from Texas
    Messages: 458

    About 4 minutes 6 seconds at 80% effeciency
  3. The Lawn Boy Pro

    The Lawn Boy Pro LawnSite Bronze Member
    Messages: 1,217

    Some 16 year old teen decided to figure it all out. I didnt figure your whole problem out, but I can if you REALLY want me to LOL:)

    Heres my acres per hour productivity @ 100% & 80% effeciency, including different deck sizes and things like so. Take your sq. footage and convert it into acres (its on the bottom of the spreadsheet) and find the acre quantity on the chart.

    Attached Files:

  4. Eric 1

    Eric 1 LawnSite Bronze Member
    Messages: 1,220

  5. Lombardi

    Lombardi LawnSite Senior Member
    Messages: 538

    3 minutes 10 seconds at 100% efficiency. This is meant as a joke because the whole idea of using a formula or spreadsheet to base your prices on is a crock. Since every lawn, every mower, every operator, the weather, the type of grass, tires, etc. is different you would have to have a formula for every single lawn. That is a waste of time. Just look at the lawn, give them a price and mow it.
    Your pricing is set by the Fair Market Value in your area. Not a computer nerd printing up spreadsheets and formulas.
  6. billc

    billc LawnSite Member
    Messages: 119

    Hey, since I work for CLIP in the winter, I resemble that remark!!

    Also, as a newbie, I'm not sure what the fair market value is in my area. I know my man-hour rate is just under $34/hour if I'm to make money this year. Say the fair market value around here is either $30/hour or $40/hour - aren't these numbers irrelevant? If I compete at $30/hour, I lose money. If I can make money at $34, then I can outbid the market if it's $40/hour.

    I figure the formula will protect me on the low end - that is, if I calculate a 10,000 sq ft lawn will take me X minutes and the formula tells me that at 100% efficiency that it will take X+ minutes, then I've done something wrong.
  7. bobbygedd

    bobbygedd LawnSite Fanatic
    from NJ
    Messages: 10,178

    there is no formula. i have 12 worth of turf that is flat, level, with no islands or obstacles, it takes less than 15 min. i have another 12 k of turf, with obstacles, it takes 25 min. there is no formula
  8. NJemerald

    NJemerald LawnSite Member
    from NJ
    Messages: 121

    Sell yourself... NOT the Price
    I agree w/ Lombardi on that chart reference!
    How many trees, planting beds, fences are there to go around?
    How spread out is the lawn? You can have 1 acre of grass spread out over a 3 acre site AND you will not do it within that time sheet spec.

    What do YOU NEED to make that lawn profitable?!

    I get more "$ per lawn" than most guys around me and thats because I sell myself AND my work!
    I do care what the other guy's $ was/is... This is what I need!

    Mind you I'm mostly residential lawns, As for commercial...
    MUCH more Cut throat!...;) which I prefer not to even bother with.
    (LIKE KNOWING I have a job EACH SEASON... :D)

    Good Luck this season!
  9. Critical Care

    Critical Care LawnSite Bronze Member
    Messages: 1,654

    Like everyone says, there are too many variables, but if you ignored them lets see what it would be.

    We know that 10000 s.f. is equal to 100' x 100'. If the Exmark actually cuts 52” wide, then that’s equal to 4.33’. It will take 100 divided by 4.33 parallel cuts. That equals to a bit over 29 times going back and forth, but lets figure 30 times to allow for a little overlap. So, 30 strips, or stripes, 100’ in length equals 30x100 or 3000 feet traveled.

    Now, the 3000 feet that the mower goes = .57 miles. And, .57 miles/ 8 mph = 0.07125 hours, or less than five minutes time. But of course, this assumes non-stop speed at 8 mph, and practically no overlap. Basically what is shown by the math is that the Exmark at 8 mph can travel 3000 in less than 5 minutes. Again… not assuming any other variables.
  10. KathysLGC

    KathysLGC LawnSite Bronze Member
    Messages: 1,345

    Don't forget to add time if your striping. You will need to go around trees/rocks watch your lines, ect..

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