What belongs in fixed costs?
Include costs that do not meaningfully change with one more sale during the chosen period: rent, base payroll, software, insurance, professional services, and other overhead. Include fixed owner compensation if the target is meant to support it.
What belongs in variable cost per sale?
Include direct labor, materials, packaging, payment fees, commissions, shipping, and similar costs caused by delivering one additional sale. Use an average that reflects the sales mix expected during the period.
Why are whole sales rounded upward?
The mathematical answer may contain a fraction, but many orders, jobs, and units are indivisible. Rounding down would knowingly leave the business short of the cost or profit target.
Can I use this for several products or services?
Only with a defensible weighted average price and variable cost based on a stable sales mix. If margins vary widely or the mix changes, calculate major offers separately or use a more detailed sales-mix model.
Does break-even mean the business has enough cash?
No. Profit and cash timing are different. Debt principal, inventory purchases, customer payment delays, tax payments, owner distributions, and capital spending can create a cash shortage even when the period is profitable. Cash runway belongs in a separate decision tool.