Three numbers: what it costs you to exist each month, what one job sells for, and what one job costs you to deliver. From there you get how many you must sell before the business stops losing money — and what your current capacity actually earns.
Rent, software, insurance, phone, your own draw — the bills that arrive whether you sell anything or not.
Materials, subcontractors, payment fees — costs that only appear when you actually do one. Enter 0 for pure services.
Your realistic capacity, not a fantasy. This is the line that tests whether break-even is reachable.
Round up: you can't sell 2.7 jobs, so 3 is the real answer. The calculator rounds for you and shows the raw figure too.
Most small service businesses are one repriced job away from break-even. Check the margin on a single job first, then the price of the whole job.