Methodology
SmallBizMath calculators are built from transparent, documented formulas — never a black box. Each cluster has its own detailed methodology page.
Pricing Methodology
Billable hours, break-even rate, reserve and margin formulas used by every pricing calculator.
Promotions Methodology
Contribution profit, contribution margin and volume-uplift formulas used by every promotion calculator.
Shared principles across every calculator
- All math runs entirely in your browser — nothing you enter is sent to a server.
- Internal calculations preserve full floating-point precision; rounding happens only for on-screen display.
- When a result is undefined or economically nonsensical (like dividing by zero revenue), the calculator explains why instead of showing NaN, Infinity or a misleading number.
- Every calculator is a planning estimate, not tax, legal, financial or accounting advice.
How to review a result
The formula is only as useful as the assumptions
Before acting on a result, identify the two or three inputs that could change most in real life. For a service rate, those are often billable utilization and annual overhead. For a promotion, they are often unit cost, redemption volume and the number of genuinely incremental orders.
Run a conservative scenario first, then a realistic scenario. If a small change in one assumption reverses the decision, treat the result as fragile and gather better data before committing. After the job or campaign, compare the estimate with the actual outcome. That feedback loop is more valuable than false precision.
Detailed pricing and promotions methodology pages document the exact definitions and formulas used by each calculator, so you can reproduce the result independently.