Your best bet is to break everything down separately. 1) Find out your trucks MPG, then figure out the mileage of your route, route mileage a week/mpg will get you what it costs to run your truck. 2) Find out what it costs to run your mower. Usually its about 1-1.25 gallons per hour. Then you will know what it costs to cut a lawn. 3) Go a week using your handhelds. At the end of the week how much gas mix did you use? Divide that by the number of lawns you did. That should give you a general idea of how much you need per lawn. 4) How many blades, oil, trimmer line etc. do you go through a week/month. Generally you change blades every 40 hours depending on the type of grass your cutting, some sooner. Oil every 50-100 hours. Find out how many hours you run a month and divide that by those two values, that should give you a good idea of what maintenance will be. 5) How much is your insurance payment. Factor that in to your monthly cost to operate. 6) How much is your finance payment. Factor that into your monthly cost to operate. 7) Divide 5 & 6 by 4, that will give you a weekly number to work with. 8) Do you have a rent/house payment? Do the same thing for this as 5/6 9) Do you want to save money? I try to shoot for 40% of my net going to bills, 20% goes back into the business, and 40% goes into savings. 10) Now that you have a weekly/monthly cost to operate, you can figure out what you need to gross to break even, and what you need to net after expenses to make a profit. So say you need $1000 a month for bills, and another $300 for gas and maintenance, that's $1300 you need to gross just to break even. Anything more than that is profit in your pocket. Honestly, you wont be able to figure out anything but your overhead until you sign some accts and start cutting.