Anywhre from zero to 50 plus. If your only mowing 15 lawns are using a push mower or a z? If ur using that z ur probbly going to lose ur ass. If your using a push ur probbly going to only make 20 an hour minus expenses. Are you driving a F350 or an el camino. You can figure out how much u can net by looking at mower efficentcies and using standard figures for repairs and gas usage, truck depreciation and stuff. BUT if you want an easy answer I would $10 but the money comes in heavy and slow at some times.
It depends on a lot of factors. In addition to what grassyfras has shared here are a couple of additional questions:
1.the 15-30 are they weekly,10 days, bi-weekly etc.
2. how close are the lawns to each other
3.how far do you have to travel to get to the lawns
4. how long does it take to do each lawn
5. what are you charging per lawn and(what is the average)
There are many other questions to be answered, but like grassyfras was saying it will really come down to knowing your expenses. When you know what you are bringing in (and when) and you know what your expenses are you will know what your cashflow looks like. When you understand your cashflow you will be able to better determine what your hourly rate will be.
You are looking at this back wards.
This is the reason that so many work so hard and so many long hours at this.
You should not enter into this or any other "JOB" with out knowing what you are going to make.
The first question you must ask yourself is how much do you need/want. Than how many hours do you want to work each week or for the year. (plan for winter).
Now do the math--- I want 40K per year--- I will be able to work 38, 40 hour weeks or= 1520 hours per year
So 40000 / 1520 = $26.32 per hour That is what you NEED TO CHARGE the business for your time.
Just add the overhead that you incur each hour and the profit that your company needs and now you know the cost to customer.
This you must do before starting your business- If you can not sell work at the price you need to, than you will have to do something else for your 40K.
This is also what most fail to do and why guys will work 80+ hours a week at $10 per hour just to make ends meet.