You need to budget your entire year for revenue and expenses.  Do the budget in the late part of your business year.  Using the previous months as a guide budget your revenue and expenses for the next year.  Include any estimated increases or decreases. Once you see the months in which you have excess cash create a plan to save some of the excess to assist you to get through the months where the cash flow is almost negative or is negative.  You could set up another bank account and transfer funds into it from the excess months and then  draw it out as needed in the negative months.  You could also approach your bank for either overdraft protection or a line of credit which you could use in the negative months.