View Full Version : Formula for calculating time to mow

billc

03-07-2004, 04:04 AM

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!

Mikes Lawn Landscape

03-07-2004, 06:51 AM

About 4 minutes 6 seconds at 80% effeciency

The Lawn Boy Pro

03-07-2004, 07:43 AM

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.

Eric 1

03-07-2004, 09:30 AM

I found this on Exmarks web site. It is very close.productivity chart (http://www.exmark.com/productivity.htm)

Lombardi

03-07-2004, 12:39 PM

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.

billc

03-07-2004, 02:45 PM

Originally posted by Lombardi

...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.

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.

bobbygedd

03-07-2004, 02:59 PM

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

NJemerald

03-07-2004, 03:17 PM

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!

Critical Care

03-07-2004, 09:57 PM

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.

KathysLGC

03-08-2004, 10:25 AM

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

brucec32

03-08-2004, 09:47 PM

Only if you were able to quantify the myriad of variables out there (such as those mentioned above, but including about 20 or 30 more) would a formula be very accurate.

The danger of formula bidding is that you will be high on some lawns and low on others. The net result of which will be that you will tend to get the jobs you bid low on and not get the ones you're high on. Meaning you will be working more for less. Hardly "efficient".

I use a baseline based on size. Then adjust it using "mark 1 eyeball" for the various other factors. The ability to do that comes with experience and cannot be done by neophytes with spreadsheets.

tiedeman

03-08-2004, 09:50 PM

I tried a lot of formulas before, and none of them worked. I finally threw away the formulas, charts, and graphs after I lost a big property.

Darryl G

03-08-2004, 10:53 PM

I don't use a formula, but as a GENERAL rule, on an average lawn in my area in the the 0.25 to 1 acre size range, it usually takes me no longer than 1/2 hour per quarter acre to mow, edge, trim and blow. But it's usually more like 20 minutes per 1/4 acre.

However, I've got one lawn that's 2 acres and takes 60 to 75 minutes and one 1/4 acre lawn that takes 50 to 60 minutes.

djlawn

03-09-2004, 10:38 AM

I don't go by some formula to mow either. Looking at the lawn is the best rule of thumb. That way if it is a very steep hill or very narrow and you have to use smaller mowers or trimmers you haven't lost your shirt. I bid a job once based on "normal size lot 1/4 acre of mowable area). That job ended up taking me an hour. I had to use a 21" hand mower for most of it because i couldn't fit through the gate to the back yard. I am trying to put a bid together for a park with about 65 acres of land. That is when pricing gets a lot more tricky.

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