Small Business Calculators
Every business decision reduces to three questions: What is this really costing me? What should I charge? Can I afford this decision? Six calculators answer them with arithmetic instead of instinct — every formula shown, every assumption stated, every result explained in plain English.
Who This Hub Is For
Owners and operators of small businesses who make real decisions with real money: service businesses, shops, agencies, freelancers and independent professionals, and anyone who signs the front of a paycheck. You do not need an accounting background — each tool starts from numbers you can pull off a bank statement or an invoice, and explains what the result means before you act on it.
Reviewed by Gerald G., founder & reviewing editor of CalcAuthority and a former small business owner. These are formula-based tools: every result is computed from the stated formula and your inputs — no hidden adjustments.
The Three Operator Questions
What is this really costing me? Overhead hides in plain sight, employees cost far more than their wage, and every fixed commitment quietly raises the revenue you need to survive. The cost side is where most bad decisions are born — not because owners can't do the math, but because the true numbers were never computed.
What should I charge? Prices set by looking sideways at competitors ignore the only economics that matter: yours. Your overhead, your margin, your billable capacity. Pricing is an equation with your survival on one side — and the equation also shows that raising prices is usually far safer than the fear suggests.
Can I afford this decision? The hire, the lease, the marketing budget — each one is really a bet against your cash runway. Knowing the runway number, the break-even number, and the payback period turns "it feels risky" into "it costs 2.1 months of runway and repays in 5."
The Workflow: Run These In Order
Start with survival math, move to pricing math, end with growth math.
- Cash Runway Calculator — how many months your business can operate at the current pace of money in and money out. The number every other decision is measured against.
- Break-Even Revenue Calculator — the monthly (and per-day) revenue at which the business stops losing money and starts earning it.
- Overhead Recovery Calculator — the invisible line item: what each billable hour, and each revenue dollar, must contribute just to keep the business standing.
- Price Increase Impact Calculator — model a price increase honestly: profit change, and exactly how many customers you could afford to lose.
- Customer Acquisition Payback Calculator — what a new customer costs to win and how many months until they repay it. Growth consumes cash before it produces cash; this is the schedule.
- Freelance Rate Builder — for independents: work backward from the income you need to the hourly rate that actually produces it.
Field Guides
The reasoning behind the tools, in plain English with worked numbers.
- Months of Cash: The One Number Every Owner Should Know
- Your Break-Even Number: The Finish Line Every Month Has
- Overhead: The Invisible Line Item That Eats Businesses
- Markup vs. Margin: The Confusion That Quietly Costs Thousands
All guides live in the Field Guides index.
How These Calculators Are Built
Every tool follows the CalcAuthority house method: the formula is stated on the page, the assumptions are listed, at least two worked examples let you verify the math by hand, verdict bands explain how to read the result, and a limitations section says what the estimate does not cover. Where a band is an editorial rule of thumb rather than a published statistic, the page says so. Full details on the Methodology page.