Below I have cut and pasted a topic that I posted on here a few years ago. 
In this trade its easy to fall into the trap of thinking that you are making more money than you actually are.You do a days work and turnover £200 or £300, the chemical costs may only be £5, plus your fuel cost, so you
“feel” that you have made a big profit.
But it can be very interesting to work out your
true NET PROFIT!Get your last set of accounts out and make a note of the
Total Expenditure amount ( the total of all of your costs, Chemicals, adverts, van and machine cost, telephone etc)
Then divide your total expenditure amount by your turnover. This will give you the percentage that your total costs are in relation to your turnover.
The results can be surprising.
So, for example,Expenditure = £10,000 divided by turnover of £50,000 = (0.2) = 20% costs
So if you turnover £50,000 in a year, but it costs you £10,000 to run the business, then for every £100 that you turnover,
£20 is actually gone to cover your running costs.So that £300 days work actually cost you £60 in costs ! That’s a bit more than most people would have guessed ?
On top of that you need to also deduct your years income tax bill ( not included in your business expenditure).
Examples.
Expenditure £10,000 – turnover £30,000 = 33.37% or
£33.37 out of
every £100 you earnExp £10,000 – T/O £40,000 = 25% ( £25 out of every £100 you T/O )
Exp 10,000 – T/O £50,000 = 20%
Exp 10,000 – T/O £60,000 = 16%
Or
Exp £13,000 – T/O £40,000 = 32.5% £32.50 out of every £100 you T/O)
Exp £13,000 – T/O £50,000 = 26%
Exp £13,000 – T/O £60,000 = 21%
Work out yours, you WILL be surprised !
Cheers
Chris
