What you can calculate in this section
Turn price, cost, volume and customer assumptions into decisions you can explain. Start with the result you need, then confirm that every input comes from the same period and uses the definition shown on the selected page.
A calculator returns a mathematical result. The worked example and limitations explain whether that result belongs in the decision you are making.
5 guides and calculators
Each page below gives the direct definition first, then the equation or method, inputs, sample calculation, common mistakes and related formulas.
Contribution Margin Formula
contribution margin formula explained with the formula, inputs, example and limitations.
Open Contribution Margin Formula →Break-Even Formula
break even formula explained with the formula, inputs, example and limitations.
Open Break-Even Formula →Marginal Cost Formula
marginal cost formula explained with the formula, inputs, example and limitations.
Open Marginal Cost Formula →Customer Lifetime Value Formula
customer lifetime value formula explained with the formula, inputs, example and limitations.
Open Customer Lifetime Value Formula →Profit Tree
profit tree explained with the formula, inputs, example and limitations.
Open Profit Tree →How to choose the right formula
- Name the decision.
Decide whether you need a value, rate, margin, return, balance or comparison. - Match the timing.
Use annual figures with annual figures and distinguish a point-in-time balance from a period flow. - Check the definition.
Confirm what each numerator, denominator, cash flow or cost includes. - Run an example.
Reproduce the sample result before entering your own figures. - Test another case.
Change one assumption at a time and record what drives the answer.
Frequently asked questions
What is business planning formulas?
Turn price, cost, volume and customer assumptions into decisions you can explain.
How should I use business planning formulas?
Use the formula only after matching every input to the same period, unit and definition. Then compare the result with a worked example and the decision you are trying to make.
What is the most common mistake with business planning formulas?
The most common mistake is choosing a familiar formula before defining the decision, period, units and available inputs.
Can I calculate business planning formulas in a spreadsheet?
Yes. Reproduce the displayed equation with separate cells for each input, keep percentages as decimals, and test the spreadsheet against the worked example before replacing the sample figures.
Sources and methodology
The section’s financial context is checked against Calculate a Break-Even Point in Units and Dollars. Each leaf page names the source used for its specific formula or reporting relationship.